":"basic","front":"What is the definition of a transition element?","back":"An element that forms at least one ion with a partially filled d sub-shell.","points":1,"mcqOptions":[{"text":"An element that forms at least one ion with a partially filled d sub-shell.","correct":true,"explanation":"Transition elements are defined by forming at least one ion whose d sub-shell is incomplete, giving rise to characteristic properties such as variable oxidation states and coloured compounds."},{"text":"An element that forms at least one ion with a completely filled d sub-shell.","correct":false,"explanation":"A full d sub-shell does not satisfy the definition of a transition element. The element must form at least one ion with a partially filled d sub-shell."},{"text":"An element that forms at least one ion with a partially filled p sub-shell.","correct":false,"explanation":"Partially filled p sub-shells characterise many p-block species, not transition elements. A transition element forms at least one ion with a partially filled d sub-shell."},{"text":"An element that forms only ions with a partially filled d sub-shell.","correct":false,"explanation":"Requiring every ion to have an incomplete d sub-shell is too restrictive; some transition elements also form d0 or d10 ions. Only one partially filled d ion is required."}]},{"id":"44e33164-fee1-4403-8499-ef2ea84640cc","cardType":"basic","front":"Why is zinc in the d-block but not typically classified as a transition element?","back":"Zinc only commonly forms $\text{Zn}^{2+}$, which has a full $3d^{10}$ sub-shell.","points":1,"mcqOptions":[{"text":"Zinc only commonly forms $\text{Zn}^{2+}$, which has a full $3d^{10}$ sub-shell.","correct":true,"explanation":"Zinc loses its two 4s electrons to form Zn2+, retaining the complete 3d10 configuration. It therefore does not form a common ion with a partially filled d sub-shell."},{"text":"Zinc only commonly forms $\\text{Zn}^{2+}$, which has a partially filled $3d^8$ sub-shell.","correct":false,"explanation":"Zn2+ has a 3d10 configuration, not 3d8, because ionisation removes zinc’s two 4s electrons first. Its full d sub-shell prevents transition-element classification."},{"text":"Zinc only commonly forms $\\text{Zn}^{2+}$, which has an empty $3d^0$ sub-shell.","correct":false,"explanation":"Removing zinc’s two 4s electrons leaves all ten 3d electrons in place, rather than emptying the d sub-shell. Zn2+ therefore has a full 3d10 sub-shell."},{"text":"Zinc only commonly forms $\\text{Zn}^{2+}$, which has a full $4s^2$ sub-shell.","correct":false,"explanation":"The 4s sub-shell is emptied when Zn2+ forms, so it is not full. The relevant feature is the remaining full 3d10 sub-shell, which is not partially filled."}]}]}],"examCountdown":{"examDate":"2027-05-28","paperLabel":"Component 1"},"heading":"Chemistry of the d-block transition metals","title":"Chemistry of the d-block transition metals Flashcards","topicSidebar":"$L41"}]}],"topicId":"c831ace1-09f5-5305-a042-7567d7007aed","walled":"$L42"}],"$L43"]