A simple molecule has the formula Q2H2\mathrm{Q_{2}H_{2}}Q2H2.
Each Q atom has the electron arrangement 2.6. Each hydrogen atom has one electron.
Three students propose models for the molecule. The models include only the electrons in the atoms' outer shells.
| Student | Shared pairs between the two Q atoms | Shared pairs between each Q atom and one H atom | Non-bonding pairs on each Q atom |
|---|---|---|---|
| A | 1 | 1 | 2 |
| B | 2 | 1 | 1 |
| C | 1 | 1 | 3 |
Evaluate the three proposed models and decide which student's model could be a correct dot-and-cross diagram.
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.