31:I[196793,["/_next/static/chunks/04dz0xqjvyj1r.js?dpl=nogit-1790430181","/_next/static/chunks/0p4rexedanx97.js?dpl=nogit-1790430181","/_next/static/chunks/2epfhfe5im7r6.js?dpl=nogit-1790430181","/_next/static/chunks/176p1wltq5_f6.js?dpl=nogit-1790430181","/_next/static/chunks/1f95q9c4h-8pl.js?dpl=nogit-1790430181","/_next/static/chunks/0u008gt6051u7.js?dpl=nogit-1790430181","/_next/static/chunks/1odwrcl12kfnl.js?dpl=nogit-1790430181","/_next/static/chunks/0zkcxwtbsqliz.js?dpl=nogit-1790430181","/_next/static/chunks/2u46tugibrk1v.js?dpl=nogit-1790430181","/_next/static/chunks/3ao1re0xmmur_.js?dpl=nogit-1790430181","/_next/static/chunks/03q735zs9dbpu.js?dpl=nogit-1790430181","/_next/static/chunks/3r5hh4t0jf4es.js?dpl=nogit-1790430181","/_next/static/chunks/3ht89vb0p09bm.js?dpl=nogit-1790430181","/_next/static/chunks/3ml3vooxhiupb.js?dpl=nogit-1790430181","/_next/static/chunks/12xoy6h_w_le6.js?dpl=nogit-1790430181","/_next/static/chunks/3jpl-42mbad5n.js?dpl=nogit-1790430181","/_next/static/chunks/2os7nxouq91eq.js?dpl=nogit-1790430181","/_next/static/chunks/3ocoqwe4aht_u.js?dpl=nogit-1790430181","/_next/static/chunks/330aj5rw-3o2w.js?dpl=nogit-1790430181","/_next/static/chunks/1h4wccj42vygd.js?dpl=nogit-1790430181","/_next/static/chunks/3xa2z7fbv2riw.js?dpl=nogit-1790430181","/_next/static/chunks/14kf-an-d2n-e.js?dpl=nogit-1790430181","/_next/static/chunks/381o-754ev9ia.js?dpl=nogit-1790430181","/_next/static/chunks/2th820ily21xq.js?dpl=nogit-1790430181","/_next/static/chunks/0v4byuex1x38h.js?dpl=nogit-1790430181","/_next/static/chunks/3kom3ps_bn2q6.js?dpl=nogit-1790430181","/_next/static/chunks/1x_yxljsdq0vl.js?dpl=nogit-1790430181","/_next/static/chunks/1xkpwfqqdrdio.js?dpl=nogit-1790430181","/_next/static/chunks/0k-y_4mcfub-p.js?dpl=nogit-1790430181","/_next/static/chunks/2dx-vzwyw9a3g.js?dpl=nogit-1790430181","/_next/static/chunks/2mv9l1xl_aa4j.js?dpl=nogit-1790430181","/_next/static/chunks/3dcuhw7_p-nlv.js?dpl=nogit-1790430181","/_next/static/chunks/04zr-wqafvwoa.js?dpl=nogit-1790430181","/_next/static/chunks/1ku-vdy4ggo41.js?dpl=nogit-1790430181","/_next/static/chunks/2a4uxh-kqx1wo.js?dpl=nogit-1790430181","/_next/static/chunks/2-3hvjs177r4z.js?dpl=nogit-1790430181","/_next/static/chunks/0llqhg6-bxn_b.js?dpl=nogit-1790430181","/_next/static/chunks/1l2yee13s4kff.js?dpl=nogit-1790430181","/_next/static/chunks/1pp_uf_jx5j9r.js?dpl=nogit-1790430181","/_next/static/chunks/1s6j_7_p0ugo9.js?dpl=nogit-1790430181","/_next/static/chunks/2vg15qyptj-oc.js?dpl=nogit-1790430181","/_next/static/chunks/2b6r02yb2zswo.js?dpl=nogit-1790430181","/_next/static/chunks/12mv6p8rwcl5o.js?dpl=nogit-1790430181","/_next/static/chunks/422ba61wql3d7.js?dpl=nogit-1790430181","/_next/static/chunks/2opkuzmjw8cxb.js?dpl=nogit-1790430181","/_next/static/chunks/34ux0fo6f-rm8.js?dpl=nogit-1790430181","/_next/static/chunks/3h4suq-9gmzwh.js?dpl=nogit-1790430181","/_next/static/chunks/0rt2_go1it43r.js?dpl=nogit-1790430181","/_next/static/chunks/0v5zhouho0zlq.js?dpl=nogit-1790430181","/_next/static/chunks/1gtlwpzgzi12z.js?dpl=nogit-1790430181","/_next/static/chunks/2zwoemojbdlmi.js?dpl=nogit-1790430181","/_next/static/chunks/2y341-r8ncizo.js?dpl=nogit-1790430181","/_next/static/chunks/3jzaxe43n3e1e.js?dpl=nogit-1790430181","/_next/static/chunks/3xz_lj7nwz2k-.js?dpl=nogit-1790430181","/_next/static/chunks/0zg1om_k0m5zv.js?dpl=nogit-1790430181","/_next/static/chunks/1lsxkfxy262n-.js?dpl=nogit-1790430181","/_next/static/chunks/1ksyn9m68446d.js?dpl=nogit-1790430181","/_next/static/chunks/2tgvlfspjb-j8.js?dpl=nogit-1790430181","/_next/static/chunks/0pdzmybpnr872.js?dpl=nogit-1790430181","/_next/static/chunks/1zt4k83kx3bkw.js?dpl=nogit-1790430181","/_next/static/chunks/200x0be4hbjpj.js?dpl=nogit-1790430181","/_next/static/chunks/35bn8r0ao86_s.js?dpl=nogit-1790430181","/_next/static/chunks/3wqp-h5xnebw9.js?dpl=nogit-1790430181","/_next/static/chunks/120-bka6zq5lp.js?dpl=nogit-1790430181","/_next/static/chunks/30dopbgd1dkf9.js?dpl=nogit-1790430181","/_next/static/chunks/43ajf4ofaeu5y.js?dpl=nogit-1790430181"],"Gingerbread"] 33:I[647935,["/_next/static/chunks/04dz0xqjvyj1r.js?dpl=nogit-1790430181","/_next/static/chunks/0p4rexedanx97.js?dpl=nogit-1790430181","/_next/static/chunks/2epfhfe5im7r6.js?dpl=nogit-1790430181","/_next/static/chunks/176p1wltq5_f6.js?dpl=nogit-1790430181","/_next/static/chunks/1f95q9c4h-8pl.js?dpl=nogit-1790430181","/_next/static/chunks/0u008gt6051u7.js?dpl=nogit-1790430181","/_next/static/chunks/1odwrcl12kfnl.js?dpl=nogit-1790430181","/_next/static/chunks/0zkcxwtbsqliz.js?dpl=nogit-1790430181","/_next/static/chunks/2u46tugibrk1v.js?dpl=nogit-1790430181","/_next/static/chunks/3ao1re0xmmur_.js?dpl=nogit-1790430181","/_next/static/chunks/03q735zs9dbpu.js?dpl=nogit-1790430181","/_next/static/chunks/3r5hh4t0jf4es.js?dpl=nogit-1790430181","/_next/static/chunks/3ht89vb0p09bm.js?dpl=nogit-1790430181","/_next/static/chunks/3ml3vooxhiupb.js?dpl=nogit-1790430181","/_next/static/chunks/12xoy6h_w_le6.js?dpl=nogit-1790430181","/_next/static/chunks/3jpl-42mbad5n.js?dpl=nogit-1790430181","/_next/static/chunks/2os7nxouq91eq.js?dpl=nogit-1790430181","/_next/static/chunks/3ocoqwe4aht_u.js?dpl=nogit-1790430181","/_next/static/chunks/330aj5rw-3o2w.js?dpl=nogit-1790430181","/_next/static/chunks/1h4wccj42vygd.js?dpl=nogit-1790430181","/_next/static/chunks/3xa2z7fbv2riw.js?dpl=nogit-1790430181","/_next/static/chunks/14kf-an-d2n-e.js?dpl=nogit-1790430181","/_next/static/chunks/381o-754ev9ia.js?dpl=nogit-1790430181","/_next/static/chunks/2th820ily21xq.js?dpl=nogit-1790430181","/_next/static/chunks/0v4byuex1x38h.js?dpl=nogit-1790430181","/_next/static/chunks/3kom3ps_bn2q6.js?dpl=nogit-1790430181","/_next/static/chunks/1x_yxljsdq0vl.js?dpl=nogit-1790430181","/_next/static/chunks/1xkpwfqqdrdio.js?dpl=nogit-1790430181","/_next/static/chunks/0k-y_4mcfub-p.js?dpl=nogit-1790430181","/_next/static/chunks/2dx-vzwyw9a3g.js?dpl=nogit-1790430181","/_next/static/chunks/2mv9l1xl_aa4j.js?dpl=nogit-1790430181","/_next/static/chunks/3dcuhw7_p-nlv.js?dpl=nogit-1790430181","/_next/static/chunks/04zr-wqafvwoa.js?dpl=nogit-1790430181","/_next/static/chunks/1ku-vdy4ggo41.js?dpl=nogit-1790430181","/_next/static/chunks/2a4uxh-kqx1wo.js?dpl=nogit-1790430181","/_next/static/chunks/2-3hvjs177r4z.js?dpl=nogit-1790430181","/_next/static/chunks/0llqhg6-bxn_b.js?dpl=nogit-1790430181","/_next/static/chunks/1l2yee13s4kff.js?dpl=nogit-1790430181","/_next/static/chunks/1pp_uf_jx5j9r.js?dpl=nogit-1790430181","/_next/static/chunks/1s6j_7_p0ugo9.js?dpl=nogit-1790430181","/_next/static/chunks/2vg15qyptj-oc.js?dpl=nogit-1790430181","/_next/static/chunks/2b6r02yb2zswo.js?dpl=nogit-1790430181","/_next/static/chunks/12mv6p8rwcl5o.js?dpl=nogit-1790430181","/_next/static/chunks/422ba61wql3d7.js?dpl=nogit-1790430181","/_next/static/chunks/2opkuzmjw8cxb.js?dpl=nogit-1790430181","/_next/static/chunks/34ux0fo6f-rm8.js?dpl=nogit-1790430181","/_next/static/chunks/3h4suq-9gmzwh.js?dpl=nogit-1790430181","/_next/static/chunks/0rt2_go1it43r.js?dpl=nogit-1790430181","/_next/static/chunks/0v5zhouho0zlq.js?dpl=nogit-1790430181","/_next/static/chunks/1gtlwpzgzi12z.js?dpl=nogit-1790430181","/_next/static/chunks/2zwoemojbdlmi.js?dpl=nogit-1790430181","/_next/static/chunks/2y341-r8ncizo.js?dpl=nogit-1790430181","/_next/static/chunks/3jzaxe43n3e1e.js?dpl=nogit-1790430181","/_next/static/chunks/3xz_lj7nwz2k-.js?dpl=nogit-1790430181","/_next/static/chunks/0zg1om_k0m5zv.js?dpl=nogit-1790430181","/_next/static/chunks/1lsxkfxy262n-.js?dpl=nogit-1790430181","/_next/static/chunks/1ksyn9m68446d.js?dpl=nogit-1790430181","/_next/static/chunks/2tgvlfspjb-j8.js?dpl=nogit-1790430181","/_next/static/chunks/0pdzmybpnr872.js?dpl=nogit-1790430181","/_next/static/chunks/1zt4k83kx3bkw.js?dpl=nogit-1790430181","/_next/static/chunks/200x0be4hbjpj.js?dpl=nogit-1790430181","/_next/static/chunks/35bn8r0ao86_s.js?dpl=nogit-1790430181","/_next/static/chunks/3wqp-h5xnebw9.js?dpl=nogit-1790430181","/_next/static/chunks/120-bka6zq5lp.js?dpl=nogit-1790430181","/_next/static/chunks/30dopbgd1dkf9.js?dpl=nogit-1790430181","/_next/static/chunks/43ajf4ofaeu5y.js?dpl=nogit-1790430181"],"RecordResourceResume"] 34:I[830476,["/_next/static/chunks/04dz0xqjvyj1r.js?dpl=nogit-1790430181","/_next/static/chunks/0p4rexedanx97.js?dpl=nogit-1790430181","/_next/static/chunks/2epfhfe5im7r6.js?dpl=nogit-1790430181","/_next/static/chunks/176p1wltq5_f6.js?dpl=nogit-1790430181","/_next/static/chunks/1f95q9c4h-8pl.js?dpl=nogit-1790430181","/_next/static/chunks/0u008gt6051u7.js?dpl=nogit-1790430181","/_next/static/chunks/1odwrcl12kfnl.js?dpl=nogit-1790430181","/_next/static/chunks/0zkcxwtbsqliz.js?dpl=nogit-1790430181","/_next/static/chunks/2u46tugibrk1v.js?dpl=nogit-1790430181","/_next/static/chunks/3ao1re0xmmur_.js?dpl=nogit-1790430181","/_next/static/chunks/03q735zs9dbpu.js?dpl=nogit-1790430181","/_next/static/chunks/3r5hh4t0jf4es.js?dpl=nogit-1790430181","/_next/static/chunks/3ht89vb0p09bm.js?dpl=nogit-1790430181","/_next/static/chunks/3ml3vooxhiupb.js?dpl=nogit-1790430181","/_next/static/chunks/12xoy6h_w_le6.js?dpl=nogit-1790430181","/_next/static/chunks/3jpl-42mbad5n.js?dpl=nogit-1790430181","/_next/static/chunks/2os7nxouq91eq.js?dpl=nogit-1790430181","/_next/static/chunks/3ocoqwe4aht_u.js?dpl=nogit-1790430181","/_next/static/chunks/330aj5rw-3o2w.js?dpl=nogit-1790430181","/_next/static/chunks/1h4wccj42vygd.js?dpl=nogit-1790430181","/_next/static/chunks/3xa2z7fbv2riw.js?dpl=nogit-1790430181","/_next/static/chunks/14kf-an-d2n-e.js?dpl=nogit-1790430181","/_next/static/chunks/381o-754ev9ia.js?dpl=nogit-1790430181","/_next/static/chunks/2th820ily21xq.js?dpl=nogit-1790430181","/_next/static/chunks/0v4byuex1x38h.js?dpl=nogit-1790430181","/_next/static/chunks/3kom3ps_bn2q6.js?dpl=nogit-1790430181","/_next/static/chunks/1x_yxljsdq0vl.js?dpl=nogit-1790430181","/_next/static/chunks/1xkpwfqqdrdio.js?dpl=nogit-1790430181","/_next/static/chunks/0k-y_4mcfub-p.js?dpl=nogit-1790430181","/_next/static/chunks/2dx-vzwyw9a3g.js?dpl=nogit-1790430181","/_next/static/chunks/2mv9l1xl_aa4j.js?dpl=nogit-1790430181","/_next/static/chunks/3dcuhw7_p-nlv.js?dpl=nogit-1790430181","/_next/static/chunks/04zr-wqafvwoa.js?dpl=nogit-1790430181","/_next/static/chunks/1ku-vdy4ggo41.js?dpl=nogit-1790430181","/_next/static/chunks/2a4uxh-kqx1wo.js?dpl=nogit-1790430181","/_next/static/chunks/2-3hvjs177r4z.js?dpl=nogit-1790430181","/_next/static/chunks/0llqhg6-bxn_b.js?dpl=nogit-1790430181","/_next/static/chunks/1l2yee13s4kff.js?dpl=nogit-1790430181","/_next/static/chunks/1pp_uf_jx5j9r.js?dpl=nogit-1790430181","/_next/static/chunks/1s6j_7_p0ugo9.js?dpl=nogit-1790430181","/_next/static/chunks/2vg15qyptj-oc.js?dpl=nogit-1790430181","/_next/static/chunks/2b6r02yb2zswo.js?dpl=nogit-1790430181","/_next/static/chunks/12mv6p8rwcl5o.js?dpl=nogit-1790430181","/_next/static/chunks/422ba61wql3d7.js?dpl=nogit-1790430181","/_next/static/chunks/2opkuzmjw8cxb.js?dpl=nogit-1790430181","/_next/static/chunks/34ux0fo6f-rm8.js?dpl=nogit-1790430181","/_next/static/chunks/3h4suq-9gmzwh.js?dpl=nogit-1790430181","/_next/static/chunks/0rt2_go1it43r.js?dpl=nogit-1790430181","/_next/static/chunks/0v5zhouho0zlq.js?dpl=nogit-1790430181","/_next/static/chunks/1gtlwpzgzi12z.js?dpl=nogit-1790430181","/_next/static/chunks/2zwoemojbdlmi.js?dpl=nogit-1790430181","/_next/static/chunks/2y341-r8ncizo.js?dpl=nogit-1790430181","/_next/static/chunks/3jzaxe43n3e1e.js?dpl=nogit-1790430181","/_next/static/chunks/3xz_lj7nwz2k-.js?dpl=nogit-1790430181","/_next/static/chunks/0zg1om_k0m5zv.js?dpl=nogit-1790430181","/_next/static/chunks/1lsxkfxy262n-.js?dpl=nogit-1790430181","/_next/static/chunks/1ksyn9m68446d.js?dpl=nogit-1790430181","/_next/static/chunks/2tgvlfspjb-j8.js?dpl=nogit-1790430181","/_next/static/chunks/0pdzmybpnr872.js?dpl=nogit-1790430181","/_next/static/chunks/1zt4k83kx3bkw.js?dpl=nogit-1790430181","/_next/static/chunks/200x0be4hbjpj.js?dpl=nogit-1790430181","/_next/static/chunks/35bn8r0ao86_s.js?dpl=nogit-1790430181","/_next/static/chunks/3wqp-h5xnebw9.js?dpl=nogit-1790430181","/_next/static/chunks/120-bka6zq5lp.js?dpl=nogit-1790430181","/_next/static/chunks/30dopbgd1dkf9.js?dpl=nogit-1790430181","/_next/static/chunks/43ajf4ofaeu5y.js?dpl=nogit-1790430181"],"FlashcardAccessBranch"] 35:I[315438,["/_next/static/chunks/04dz0xqjvyj1r.js?dpl=nogit-1790430181","/_next/static/chunks/0p4rexedanx97.js?dpl=nogit-1790430181","/_next/static/chunks/2epfhfe5im7r6.js?dpl=nogit-1790430181","/_next/static/chunks/176p1wltq5_f6.js?dpl=nogit-1790430181","/_next/static/chunks/1f95q9c4h-8pl.js?dpl=nogit-1790430181","/_next/static/chunks/0u008gt6051u7.js?dpl=nogit-1790430181","/_next/static/chunks/1odwrcl12kfnl.js?dpl=nogit-1790430181","/_next/static/chunks/0zkcxwtbsqliz.js?dpl=nogit-1790430181","/_next/static/chunks/2u46tugibrk1v.js?dpl=nogit-1790430181","/_next/static/chunks/3ao1re0xmmur_.js?dpl=nogit-1790430181","/_next/static/chunks/03q735zs9dbpu.js?dpl=nogit-1790430181","/_next/static/chunks/3r5hh4t0jf4es.js?dpl=nogit-1790430181","/_next/static/chunks/3ht89vb0p09bm.js?dpl=nogit-1790430181","/_next/static/chunks/3ml3vooxhiupb.js?dpl=nogit-1790430181","/_next/static/chunks/12xoy6h_w_le6.js?dpl=nogit-1790430181","/_next/static/chunks/3jpl-42mbad5n.js?dpl=nogit-1790430181","/_next/static/chunks/2os7nxouq91eq.js?dpl=nogit-1790430181","/_next/static/chunks/3ocoqwe4aht_u.js?dpl=nogit-1790430181","/_next/static/chunks/330aj5rw-3o2w.js?dpl=nogit-1790430181","/_next/static/chunks/1h4wccj42vygd.js?dpl=nogit-1790430181","/_next/static/chunks/3xa2z7fbv2riw.js?dpl=nogit-1790430181","/_next/static/chunks/14kf-an-d2n-e.js?dpl=nogit-1790430181","/_next/static/chunks/381o-754ev9ia.js?dpl=nogit-1790430181","/_next/static/chunks/2th820ily21xq.js?dpl=nogit-1790430181","/_next/static/chunks/0v4byuex1x38h.js?dpl=nogit-1790430181","/_next/static/chunks/3kom3ps_bn2q6.js?dpl=nogit-1790430181","/_next/static/chunks/1x_yxljsdq0vl.js?dpl=nogit-1790430181","/_next/static/chunks/1xkpwfqqdrdio.js?dpl=nogit-1790430181","/_next/static/chunks/0k-y_4mcfub-p.js?dpl=nogit-1790430181","/_next/static/chunks/2dx-vzwyw9a3g.js?dpl=nogit-1790430181","/_next/static/chunks/2mv9l1xl_aa4j.js?dpl=nogit-1790430181","/_next/static/chunks/3dcuhw7_p-nlv.js?dpl=nogit-1790430181","/_next/static/chunks/04zr-wqafvwoa.js?dpl=nogit-1790430181","/_next/static/chunks/1ku-vdy4ggo41.js?dpl=nogit-1790430181","/_next/static/chunks/2a4uxh-kqx1wo.js?dpl=nogit-1790430181","/_next/static/chunks/2-3hvjs177r4z.js?dpl=nogit-1790430181","/_next/static/chunks/0llqhg6-bxn_b.js?dpl=nogit-1790430181","/_next/static/chunks/1l2yee13s4kff.js?dpl=nogit-1790430181","/_next/static/chunks/1pp_uf_jx5j9r.js?dpl=nogit-1790430181","/_next/static/chunks/1s6j_7_p0ugo9.js?dpl=nogit-1790430181","/_next/static/chunks/2vg15qyptj-oc.js?dpl=nogit-1790430181","/_next/static/chunks/2b6r02yb2zswo.js?dpl=nogit-1790430181","/_next/static/chunks/12mv6p8rwcl5o.js?dpl=nogit-1790430181","/_next/static/chunks/422ba61wql3d7.js?dpl=nogit-1790430181","/_next/static/chunks/2opkuzmjw8cxb.js?dpl=nogit-1790430181","/_next/static/chunks/34ux0fo6f-rm8.js?dpl=nogit-1790430181","/_next/static/chunks/3h4suq-9gmzwh.js?dpl=nogit-1790430181","/_next/static/chunks/0rt2_go1it43r.js?dpl=nogit-1790430181","/_next/static/chunks/0v5zhouho0zlq.js?dpl=nogit-1790430181","/_next/static/chunks/1gtlwpzgzi12z.js?dpl=nogit-1790430181","/_next/static/chunks/2zwoemojbdlmi.js?dpl=nogit-1790430181","/_next/static/chunks/2y341-r8ncizo.js?dpl=nogit-1790430181","/_next/static/chunks/3jzaxe43n3e1e.js?dpl=nogit-1790430181","/_next/static/chunks/3xz_lj7nwz2k-.js?dpl=nogit-1790430181","/_next/static/chunks/0zg1om_k0m5zv.js?dpl=nogit-1790430181","/_next/static/chunks/1lsxkfxy262n-.js?dpl=nogit-1790430181","/_next/static/chunks/1ksyn9m68446d.js?dpl=nogit-1790430181","/_next/static/chunks/2tgvlfspjb-j8.js?dpl=nogit-1790430181","/_next/static/chunks/0pdzmybpnr872.js?dpl=nogit-1790430181","/_next/static/chunks/1zt4k83kx3bkw.js?dpl=nogit-1790430181","/_next/static/chunks/200x0be4hbjpj.js?dpl=nogit-1790430181","/_next/static/chunks/35bn8r0ao86_s.js?dpl=nogit-1790430181","/_next/static/chunks/3wqp-h5xnebw9.js?dpl=nogit-1790430181","/_next/static/chunks/120-bka6zq5lp.js?dpl=nogit-1790430181","/_next/static/chunks/30dopbgd1dkf9.js?dpl=nogit-1790430181","/_next/static/chunks/43ajf4ofaeu5y.js?dpl=nogit-1790430181"],"TopicFlashcardRunner"] 22:[["$","$L31",null,{"feature":"flashcards"}],"$L32",["$","$L33",null,{"href":"/igcse/chemistry/edexcel/covalent-bonding/flashcards","label":"Covalent bonding","subjectCode":"igcse_chemistry","surface":"flashcards"}],["$","$L34",null,{"runner":["$","div",null,{"className":"min-h-0 flex-1 overflow-hidden bg-background","children":["$","$L35",null,{"decks":[{"id":"a8bc40a2-0b6e-4c8b-a940-1e903fb064e7","title":"Covalent bonding Flashcards","topicId":"8431689c-3f49-5cee-b6dd-527a14132706","topicSlug":"covalent-bonding","cards":[{"id":"9a1cbb93-55b0-4469-b61e-bc8f442dbfe9","cardType":"cloze","points":null,"front":"For main-group elements, the group number tells you the number of [ ].","back":"For main-group elements, the group number tells you the number of outer-shell electrons.","mcqOptions":[{"text":"outer-shell electrons","correct":true,"explanation":"Main-group elements have a group number linked to the number of electrons in their highest occupied shell. These electrons determine much of the element’s chemical behaviour and bonding."},{"text":"electron shells","correct":false,"explanation":"The number of occupied shells is related to an element’s period, not its group. The group number instead indicates the number of outer-shell electrons for main-group elements."},{"text":"protons","correct":false,"explanation":"The group number does not count positively charged particles in the nucleus. It indicates the number of outer-shell electrons for main-group elements."},{"text":"bonding pairs","correct":false,"explanation":"Bonding pairs form between atoms, but their number is not directly given by the group number. For main-group elements, the group number shows outer-shell electrons."}]},{"id":"9d155288-be0b-4922-8f68-03bdb02637f4","cardType":"basic","points":1,"front":"Which type of atoms usually form covalent bonds?","back":"Non-metal atoms.","mcqOptions":[{"text":"Non-metal atoms.","correct":true,"explanation":"Covalent bonding normally occurs between non-metal atoms. Their atoms share electrons to achieve more stable outer electron arrangements rather than forming a metallic lattice or transferring electrons."},{"text":"Metal atoms","correct":false,"explanation":"Metal atoms usually form metallic bonds or ionic compounds, rather than sharing electron pairs in typical covalent molecules. The expected answer is non-metal atoms."},{"text":"Noble-gas atoms","correct":false,"explanation":"Noble gases generally have full outer shells and are unreactive, so they rarely form ordinary covalent bonds. Covalent bonds usually involve non-metal atoms."},{"text":"Hydrogen atoms","correct":false,"explanation":"Hydrogen can take part in covalent bonding, but it is only one example and is not the general category. The usual bonding atoms are non-metal atoms."}]},{"id":"ba9d91cf-1a5b-4e5e-9e89-f5c480326624","cardType":"cloze","points":null,"front":"A covalent bond forms when atoms share [ ].","back":"A covalent bond forms when atoms share a pair of electrons.","mcqOptions":[{"text":"a pair of electrons","correct":true,"explanation":"A covalent bond consists of one shared pair of electrons. Each atom contributes an electron to the pair, which is attracted to both positively charged nuclei."},{"text":"an electron","correct":false,"explanation":"A single electron cannot normally make the shared pair that defines a covalent bond. The correct description is a pair of electrons shared between atoms."},{"text":"a pair of protons","correct":false,"explanation":"Covalent bonds involve sharing electrons, not transferring protons. The shared particles are a pair of electrons attracted to both nuclei."},{"text":"a pair of neutrons","correct":false,"explanation":"A pair of neutrons is found in nuclei and does not participate in chemical bonding. Covalent bonds form when atoms share a pair of electrons."}]},{"id":"62a9a4a4-e2aa-4df2-b18a-908971dae3b9","cardType":"cloze","points":null,"front":"A covalent bond is held by electrostatic attraction between the shared electrons and the [ ].","back":"A covalent bond is held by electrostatic attraction between the shared electrons and the nuclei of the bonded atoms.","mcqOptions":[{"text":"nuclei of the bonded atoms","correct":true,"explanation":"The shared electrons are negatively charged and are attracted to the positively charged nuclei of both bonded atoms. This electrostatic attraction holds the covalent bond together."},{"text":"outer-shell electrons","correct":false,"explanation":"The shared electrons repel other electrons because they have the same charge. The attractive force in a covalent bond is between the electrons and the nuclei of the bonded atoms."},{"text":"ions of the bonded atoms","correct":false,"explanation":"Neutral covalent atoms do not usually provide oppositely charged ions within the bond. Attraction occurs between shared electrons and the nuclei of the bonded atoms."},{"text":"electron clouds of the bonded atoms","correct":false,"explanation":"Electron clouds are negatively charged and would repel the shared electrons. The stabilising attraction is directed towards the positively charged nuclei of the bonded atoms."}]},{"id":"4772fc9e-7b05-4269-9891-963ad072be1f","cardType":"basic","points":1,"front":"What do dots and crosses show in a dot-and-cross diagram?","back":"The atom each electron originally came from.","mcqOptions":[{"text":"The atom each electron originally came from.","correct":true,"explanation":"Dots and crosses distinguish the sources of electrons in a dot-and-cross diagram. They show which atom originally supplied each electron in the covalent bond."},{"text":"The charge on each atom.","correct":false,"explanation":"Dots and crosses do not show whether an atom is positively or negatively charged. They identify the atom each electron originally came from in the diagram."},{"text":"The energy level of each electron.","correct":false,"explanation":"The symbols do not represent different energy levels or shells. They distinguish which atom originally contributed each electron to the shared pair."},{"text":"The number of bonds each atom forms.","correct":false,"explanation":"The symbols do not indicate the number of bonds an atom can form. They show the original source of each electron represented in the diagram."}]},{"id":"adfc7f35-283c-4980-acb8-3b18d74dcc1a","cardType":"cloze","points":null,"front":"A lone pair is a pair of outer electrons [ ].","back":"A lone pair is a pair of outer electrons not used in bonding.","mcqOptions":[{"text":"not used in bonding","correct":true,"explanation":"A lone pair contains two outer-shell electrons that remain on one atom instead of being shared in a covalent bond. It can affect molecular shape and polarity."},{"text":"used in bonding","correct":false,"explanation":"Electrons used in bonding form a shared pair between atoms, so they are not lone-pair electrons. A lone pair is not used in bonding."},{"text":"transferred between atoms","correct":false,"explanation":"A lone pair remains associated with one atom rather than being transferred to another atom. The defining feature is that it is not used in bonding."},{"text":"found inside the nucleus","correct":false,"explanation":"A lone pair is not necessarily located inside the nucleus; outer electrons occupy regions around the nucleus. It consists of electrons not used in bonding."}]},{"id":"4fb20d29-afe8-408d-9459-ab173995b4d5","cardType":"basic","points":1,"front":"What bond is present in an oxygen molecule, $O_2$?","back":"A double bond - two shared pairs.","mcqOptions":[{"text":"A double bond - two shared pairs.","correct":true,"explanation":"Each oxygen atom needs two more electrons for a full outer shell, so the atoms share two electron pairs. This creates a double covalent bond."},{"text":"A single bond - one shared pair.","correct":false,"explanation":"A single bond would provide only one shared pair, leaving each oxygen atom short of a full outer shell. Oxygen molecules contain a double bond."},{"text":"A triple bond - three shared pairs.","correct":false,"explanation":"Three shared pairs would give oxygen more shared electrons than required for its usual molecule. The bond in $O_2$ is double, with two shared pairs."},{"text":"A coordinate bond - one shared pair.","correct":false,"explanation":"A coordinate bond is a covalent bond where both electrons in a pair come from one atom, but $O_2$ is represented with two ordinary shared pairs."}]},{"id":"67652304-1204-4712-a12b-9133ad2ce10b","cardType":"basic","points":1,"front":"What bond is present in a nitrogen molecule, $N_2$?","back":"A triple bond - three shared pairs.","mcqOptions":[{"text":"A triple bond - three shared pairs.","correct":true,"explanation":"Each nitrogen atom needs three more electrons for a full outer shell, so the atoms share three electron pairs. This produces a triple covalent bond in $N_2$."},{"text":"A single bond - one shared pair.","correct":false,"explanation":"One shared pair would not provide enough electrons for each nitrogen atom to complete its outer shell. Nitrogen molecules contain three shared pairs."},{"text":"A double bond - two shared pairs.","correct":false,"explanation":"Two shared pairs still leave each nitrogen atom one electron short of a full outer shell. The bond in $N_2$ is triple, not double."},{"text":"A coordinate bond - one shared pair.","correct":false,"explanation":"A coordinate bond describes how a shared pair may be supplied, not the total bond order in nitrogen. $N_2$ has three shared pairs forming a triple bond."}]},{"id":"f73032ef-5bf8-4837-8ebe-bf89e8bd7e3f","cardType":"basic","points":1,"front":"In a halogen molecule such as $Cl_2$, how many lone pairs does each halogen have?","back":"Three lone pairs.","mcqOptions":[{"text":"Three lone pairs.","correct":true,"explanation":"Each chlorine atom has seven outer-shell electrons and shares one electron in the Cl-Cl bond. The remaining six electrons form three lone pairs around each chlorine atom."},{"text":"Two lone pairs.","correct":false,"explanation":"Two lone pairs would leave each halogen with only six non-bonding electrons, so its outer shell would not be complete. Each chlorine instead has three lone pairs."},{"text":"One lone pair.","correct":false,"explanation":"A single lone pair accounts for only two non-bonding electrons and does not complete the halogen’s outer shell. After bonding, each halogen retains three lone pairs."},{"text":"Four lone pairs.","correct":false,"explanation":"Four lone pairs would give each halogen too many electrons after forming the covalent bond. A halogen molecule has three lone pairs on each atom."}]},{"id":"c7e9df73-5864-4b9d-8c00-78744499174b","cardType":"basic","points":1,"front":"In water, $H_2O$, how many lone pairs are on oxygen?","back":"Two lone pairs.","mcqOptions":[{"text":"Two lone pairs.","correct":true,"explanation":"Oxygen has six outer-shell electrons and forms two O-H bonds in water. The remaining four electrons stay on oxygen as two lone pairs."},{"text":"One lone pair.","correct":false,"explanation":"One lone pair would account for only two of oxygen’s four non-bonding electrons. The two O-H bonds leave oxygen with two lone pairs, not one."},{"text":"Three lone pairs.","correct":false,"explanation":"Three lone pairs would give oxygen too many electrons when combined with its two O-H bonds. Water has two lone pairs on oxygen."},{"text":"Four lone pairs.","correct":false,"explanation":"Oxygen in water does not have four lone pairs; that would exceed its normal outer-shell electron count. Its two bonds are accompanied by two lone pairs."}]},{"id":"c54e8573-c123-47a0-baed-7bcb25264321","cardType":"basic","points":1,"front":"In ammonia, $NH_3$, how many lone pairs are on nitrogen?","back":"One lone pair.","mcqOptions":[{"text":"One lone pair.","correct":true,"explanation":"Nitrogen has five outer-shell electrons and forms three N-H bonds in ammonia. The remaining two electrons stay together as one lone pair."},{"text":"Two lone pairs.","correct":false,"explanation":"Nitrogen’s three N-H bonds use three shared electron pairs, but nitrogen still has two non-bonding electrons. These form one lone pair, not two."},{"text":"No lone pairs.","correct":false,"explanation":"No lone pair would leave nitrogen with only six electrons around it from the three N-H bonds. Ammonia has one remaining lone pair on nitrogen."},{"text":"Three lone pairs.","correct":false,"explanation":"Three lone pairs would give nitrogen more electrons than its normal outer shell can accommodate alongside three N-H bonds. Only one lone pair remains."}]},{"id":"e8339ba7-b118-42b2-a767-eeb24ba71b12","cardType":"basic","points":1,"front":"What is the covalent structure of carbon dioxide, $CO_2$?","back":"The structure is O=C=O.","mcqOptions":[{"text":"The structure is O=C=O.","correct":true,"explanation":"Carbon dioxide has two carbon-oxygen double bonds, giving the covalent structure O=C=O. Each atom achieves a stable outer electron arrangement."},{"text":"The structure is O-C=O.","correct":false,"explanation":"A structure with one single and one double bond would not give both oxygen atoms the correct stable arrangement in carbon dioxide. The molecule contains two C=O double bonds."},{"text":"The structure is O-C-O.","correct":false,"explanation":"Two single C-O bonds do not provide enough shared electrons for carbon and the oxygen atoms to complete their outer shells. Carbon dioxide is represented with two double bonds."},{"text":"The structure is O=C-O.","correct":false,"explanation":"Reversing the bonding symbols does not represent carbon dioxide’s two double bonds; it would place the single bonds incorrectly. The correct arrangement is O=C=O."}]},{"id":"975fe0c7-571b-4b68-b99c-fd83b55503cb","cardType":"cloze","points":null,"front":"In methane, $CH_4$, carbon forms [ ].","back":"In methane, $CH_4$, carbon forms four single C-H bonds.","mcqOptions":[{"text":"four single C-H bonds","correct":true,"explanation":"Carbon has four outer-shell electrons and therefore shares one electron with each of four hydrogen atoms. These shared pairs form four single C-H covalent bonds."},{"text":"four double C-H bonds","correct":false,"explanation":"Carbon does not form four double bonds in methane; that would give it far too many shared electrons. Each hydrogen forms one single bond to carbon."},{"text":"three single C-H bonds","correct":false,"explanation":"Methane contains four hydrogen atoms, so carbon forms four bonds rather than three. Each is a single C-H bond, giving carbon a complete outer shell."},{"text":"one C=C bond","correct":false,"explanation":"Carbon in methane uses all four available bonding electrons to form four C-H bonds. It therefore has no C=C bond or additional carbon atom."}]},{"id":"8cead801-8256-4096-bafa-abaa658186ac","cardType":"cloze","points":null,"front":"In ethene, $C_2H_4$, the two carbon atoms are joined by a [ ].","back":"In ethene, $C_2H_4$, the two carbon atoms are joined by a C=C double bond.","mcqOptions":[{"text":"C=C double bond","correct":true,"explanation":"Ethene contains a shared pair of electron pairs between its two carbon atoms, represented as C=C. This double bond allows each carbon to complete its outer shell."},{"text":"C-C single bond","correct":false,"explanation":"A single C-C bond is present in ethane, C2H6, rather than ethene. Ethene has fewer hydrogen atoms because its two carbons are joined by a double bond."},{"text":"C-C-C chain","correct":false,"explanation":"Ethene has only two carbon atoms, so it cannot contain a C-C-C chain. Its carbon atoms are directly joined by a C=C double bond."},{"text":"C≡C triple bond","correct":false,"explanation":"A C≡C triple bond is characteristic of ethyne, C2H2. Ethene, C2H4, contains a double bond between its carbon atoms."}]},{"id":"7846fafb-c1f0-4921-94c0-9bf2d8e4c525","cardType":"cloze","points":null,"front":"In simple molecular substances, strong covalent bonds are inside molecules, while weak intermolecular forces act [ ].","back":"In simple molecular substances, strong covalent bonds are inside molecules, while weak intermolecular forces act between separate molecules.","mcqOptions":[{"text":"between separate molecules","correct":true,"explanation":"Covalent bonds hold atoms together within each molecule, whereas intermolecular forces are attractions between distinct molecules. These intermolecular forces are much weaker."},{"text":"inside the same molecule","correct":false,"explanation":"Intermolecular forces do not act inside a molecule; covalent bonds provide the strong internal attractions there. Intermolecular forces act between separate molecules."},{"text":"inside atomic nuclei","correct":false,"explanation":"The nucleus is not the location of intermolecular attractions. These weak forces occur between molecules, while covalent bonds act between atoms within a molecule."},{"text":"between atoms in one molecule","correct":false,"explanation":"Intermolecular forces are not restricted to the atoms at the ends of one molecule. The term describes attractions between separate molecules in the substance."}]},{"id":"6effe50f-fcd5-4c0b-96ac-82f88ebb7dda","cardType":"basic","points":2,"front":"Why do simple molecular substances usually have low melting and boiling points?","back":"Weak intermolecular forces between molecules need little energy to overcome.","mcqOptions":[{"text":"Weak intermolecular forces between molecules need little energy to overcome.","correct":true,"explanation":"Simple molecular substances have weak attractions between their molecules. Only a small amount of energy is needed to overcome these intermolecular forces during melting or boiling."},{"text":"Strong covalent bonds between molecules need little energy to overcome.","correct":false,"explanation":"The covalent bonds inside molecules are strong and are not usually broken when a simple molecular substance melts or boils. Weak intermolecular forces require little energy to overcome."},{"text":"Strong ionic forces between molecules need little energy to overcome.","correct":false,"explanation":"Simple molecular substances do not usually contain strong ionic attractions between molecules. Their low melting and boiling points result from weak intermolecular forces."},{"text":"Weak covalent bonds between molecules need little energy to overcome.","correct":false,"explanation":"The molecules themselves are not generally weakly bonded internally; their covalent bonds are strong. It is the weak forces between molecules that are overcome easily."}]},{"id":"ac1c0568-8a77-4ac5-beb1-09af4b986a34","cardType":"basic","points":2,"front":"Predict the effect of increasing $M_r$ on boiling point.","back":"Boiling point increases because intermolecular forces become stronger.","mcqOptions":[{"text":"Boiling point increases because intermolecular forces become stronger.","correct":true,"explanation":"Larger molecules usually contain more electrons and are more polarisable, producing stronger London dispersion forces. More energy is therefore needed to separate the molecules."},{"text":"Boiling point decreases because intermolecular forces become weaker.","correct":false,"explanation":"Greater relative molecular mass generally strengthens, rather than weakens, London dispersion forces. The boiling point increases because more energy is required to overcome these forces."},{"text":"Boiling point stays constant because covalent bond strength is unchanged.","correct":false,"explanation":"This confuses intramolecular covalent bonds with the intermolecular forces overcome during boiling. As relative molecular mass increases, stronger intermolecular forces generally raise the boiling point."},{"text":"Boiling point decreases because intermolecular forces become stronger.","correct":false,"explanation":"Stronger intermolecular forces require more energy to overcome, so they cannot cause a lower boiling point. Increasing relative molecular mass generally makes the boiling point increase."}]},{"id":"f68d5cd9-f5e0-4c99-bc50-179b2e40cb08","cardType":"basic","points":2,"front":"Why do giant covalent structures have very high melting and boiling points?","back":"Many strong covalent bonds must be broken, requiring lots of energy.","mcqOptions":[{"text":"Many strong covalent bonds must be broken, requiring lots of energy.","correct":true,"explanation":"A giant covalent structure contains a continuous network of strong covalent bonds. Melting or boiling it requires many of these bonds to break, demanding substantial energy."},{"text":"Many weak intermolecular forces must be broken, requiring lots of energy.","correct":false,"explanation":"Giant covalent structures are not made from separate molecules held together by weak forces. Many strong covalent bonds in the continuous network must be broken."},{"text":"Strong covalent bonds between molecules must be broken, requiring lots of energy.","correct":false,"explanation":"Covalent bonds occur between atoms within the giant network, not between separate molecules. Breaking many of these strong bonds requires the large energy input."},{"text":"Individual carbon atoms must be broken apart, requiring lots of energy.","correct":false,"explanation":"Melting does not require atomic nuclei to split apart. It requires many strong covalent bonds connecting atoms throughout the giant structure to be broken."}]},{"id":"382df4d6-0a17-4ffe-bc7e-58c127961cfd","cardType":"cloze","points":null,"front":"In diamond, each carbon atom forms [ ] to other carbon atoms in a three-dimensional network.","back":"In diamond, each carbon atom forms four covalent bonds to other carbon atoms in a three-dimensional network.","mcqOptions":[{"text":"four covalent bonds","correct":true,"explanation":"Carbon has four outer-shell electrons and shares each one with another carbon atom in diamond, forming four covalent bonds in a tetrahedral network."},{"text":"three covalent bonds","correct":false,"explanation":"Three covalent bonds are formed by each carbon atom in graphite, leaving one electron delocalised. In diamond, each carbon instead forms four covalent bonds."},{"text":"four ionic bonds","correct":false,"explanation":"Diamond consists of carbon atoms sharing electron pairs, so its bonding is covalent rather than ionic. Each carbon atom forms four covalent bonds."},{"text":"six covalent bonds","correct":false,"explanation":"Carbon cannot form six ordinary covalent bonds because it has only four outer-shell electrons available for bonding. Each carbon in diamond forms four covalent bonds."}]},{"id":"ebe5b555-1ae1-4d7c-9142-33fa7781b6e4","cardType":"basic","points":2,"front":"Why is diamond very hard?","back":"Its atoms are held in a rigid three-dimensional covalent network.","mcqOptions":[{"text":"Its atoms are held in a rigid three-dimensional covalent network.","correct":true,"explanation":"Strong covalent bonds hold every carbon atom firmly in a fixed three-dimensional arrangement. This rigid network resists deformation, making diamond exceptionally hard."},{"text":"Its atoms are held in closely packed layers by metallic bonds.","correct":false,"explanation":"Diamond does not contain metallic bonding or closely packed layers. Its hardness results from strong covalent bonds extending through a rigid three-dimensional network."},{"text":"Its molecules are held by strong intermolecular forces.","correct":false,"explanation":"Diamond is a giant covalent structure, not a collection of separate molecules. Its atoms are fixed by strong covalent bonds throughout a three-dimensional network."},{"text":"Its layers are held by weak intermolecular forces.","correct":false,"explanation":"Weak forces between layers describe graphite and allow its layers to slide, making it soft. Diamond is hard because it has a rigid three-dimensional covalent network."}]},{"id":"07ad410d-dbe3-4f0c-b859-bfc03a6c2a8e","cardType":"basic","points":1,"front":"Why does diamond not conduct electricity?","back":"It has no mobile charged particles.","mcqOptions":[{"text":"It has no mobile charged particles.","correct":true,"explanation":"All four outer-shell electrons from each carbon atom are localised in covalent bonds. With no mobile ions or delocalised electrons, diamond cannot carry electric charge."},{"text":"It has no electrons in its structure.","correct":false,"explanation":"Diamond contains electrons, but they are localised within covalent bonds rather than free to move. It fails to conduct because it has no mobile charged particles."},{"text":"It has strong covalent bonds that block current.","correct":false,"explanation":"Strong bonds do not physically block an electric current. Diamond cannot conduct because its electrons are localised in those bonds, leaving no mobile charged particles."},{"text":"It has no spaces for electrons to move through.","correct":false,"explanation":"Electrical conduction does not require empty spaces through which electrons can travel. Diamond lacks mobile ions or delocalised electrons capable of carrying charge."}]},{"id":"3ebbe8df-86ae-492c-925d-4c57d8e403d4","cardType":"basic","points":2,"front":"Why can graphite conduct electricity along its layers?","back":"Delocalised electrons move along layers and carry charge.","mcqOptions":[{"text":"Delocalised electrons move along layers and carry charge.","correct":true,"explanation":"Each carbon in graphite contributes one electron to a delocalised system. These electrons can move along a layer and transfer electrical charge through the structure."},{"text":"Positively charged carbon ions move along layers and carry charge.","correct":false,"explanation":"The carbon atoms remain fixed in their covalent layers and do not become mobile ions. Charge is carried by delocalised electrons moving along the layers."},{"text":"Covalent bonds move along layers and carry charge.","correct":false,"explanation":"Covalent bonds are connections between atoms and cannot move through the structure. Mobile delocalised electrons travel along graphite’s layers and carry the charge."},{"text":"Delocalised electrons move between layers and carry charge.","correct":false,"explanation":"Graphite conducts much better along its layers because its delocalised electrons move mainly within them. Weakly connected layers do not provide the principal conduction pathway."}]},{"id":"0f828ed6-2678-4814-971b-f77569554da5","cardType":"basic","points":2,"front":"Why is graphite soft and slippery?","back":"Weak forces between layers let the layers slide.","mcqOptions":[{"text":"Weak forces between layers let the layers slide.","correct":true,"explanation":"Strong covalent bonds hold carbon atoms together within each layer, but only weak forces act between layers. The layers therefore slide over one another easily."},{"text":"Strong covalent bonds within layers let the layers slide.","correct":false,"explanation":"Strong covalent bonds maintain the structure of each individual layer but do not cause sliding. Sliding occurs because only weak forces hold neighbouring layers together."},{"text":"Weak forces within layers let the atoms slide.","correct":false,"explanation":"Forces within each graphite layer are strong covalent bonds, so atoms do not slide within a layer. Weak forces between whole layers allow them to move."},{"text":"Delocalised electrons between layers let the layers slide.","correct":false,"explanation":"Delocalised electrons enable electrical conduction but do not act as a lubricant between layers. Graphite is slippery because weak interlayer forces allow sliding."}]},{"id":"8e6ca319-0dff-4ad9-9d84-34934cf984ef","cardType":"cloze","points":null,"front":"$$C_{60}$ fullerene is made of molecules containing [ ].","back":"$$C_{60}$ fullerene is made of molecules containing 60 carbon atoms arranged in a hollow sphere.","mcqOptions":[{"text":"60 carbon atoms arranged in a hollow sphere","correct":true,"explanation":"A buckminsterfullerene molecule contains exactly 60 carbon atoms joined in a hollow, roughly spherical cage made from pentagonal and hexagonal rings."},{"text":"60 carbon atoms arranged in a flat sheet","correct":false,"explanation":"A flat sheet of carbon atoms describes graphene rather than a fullerene cage. A $C_{60}$ molecule contains 60 atoms arranged in a hollow sphere."},{"text":"70 carbon atoms arranged in a hollow sphere","correct":false,"explanation":"The subscript in $C_{60}$ specifies 60 carbon atoms, not 70. These 60 atoms form a hollow spherical cage; 70 atoms would represent $C_{70}$."},{"text":"60 carbon atoms arranged in a hollow cylinder","correct":false,"explanation":"A hollow cylindrical carbon structure is a nanotube, not $C_{60}$ fullerene. The 60 carbon atoms in $C_{60}$ form a hollow spherical cage."}]},{"id":"87e8c28a-9996-4533-a876-f2a4b4c57070","cardType":"basic","points":2,"front":"Why does $C_{60}$ fullerene have a much lower melting point than diamond or graphite?","back":"Weak intermolecular forces act between separate $C_{60}$ molecules.","mcqOptions":[{"text":"Weak intermolecular forces act between separate $C_{60}$ molecules.","correct":true,"explanation":"Each $C_{60}$ molecule has strong covalent bonds internally, but only weak intermolecular forces connect different molecules. Melting requires little energy because only these weak forces are overcome."},{"text":"Weak covalent bonds act within individual $C_{60}$ molecules.","correct":false,"explanation":"The covalent bonds within each $C_{60}$ molecule are strong, not weak, and are not broken during melting. The low melting point results from weak intermolecular forces between separate molecules."},{"text":"Strong covalent bonds act between separate $C_{60}$ molecules.","correct":false,"explanation":"Separate $C_{60}$ molecules are not joined by strong covalent bonds. Unlike diamond and graphite, fullerene is molecular, so only weak intermolecular forces must be overcome during melting."},{"text":"Weak ionic attractions act between oppositely charged $C_{60}$ ions.","correct":false,"explanation":"Fullerene does not consist of ions, so ionic attractions do not determine its melting point. Its separate $C_{60}$ molecules are held together by weak intermolecular forces requiring relatively little energy to overcome."}]}]}],"examCountdown":{"examDate":"2027-05-19","paperLabel":"Paper 1"},"heading":"Covalent bonding","title":"Covalent bonding Flashcards","topbar":{"backHref":"/igcse/chemistry/edexcel/flashcards"},"topicSidebar":"$L36"}]}],"topicId":"8431689c-3f49-5cee-b6dd-527a14132706","walled":"$L37"}],"$L38","$L39"]