Aluminium is a metal in Group 3. Selenium is a non-metal in Group 6. They react to form an ionic compound.
A student's proposed dot and cross representation is summarised in the table.
| Feature | Student's proposal |
|---|---|
| Aluminium ions | two ions, each with charge 2+ |
| Selenium ions | three ions, each with charge 2− |
| Outer electrons around each selenium ion | six dots and one cross |
Evaluate the student's proposed representation. Use electron transfer and charge balance in your answer.
122 exam-style questions on OCR GCSE Chemistry 2.2 Bonding, covering 2.2.1 Metals, non-metals and the Periodic Table, 2.2.2 Types of chemical bonding and dot and cross diagrams, 2.2.3 Limitations of bonding models, and 2.2.4 Reactivity, atomic number and the modern Periodic Table. Each one has a worked solution and a mark scheme showing where the marks go.