DP Chemistry (first assessment 2025)
Question 22M.2.SL.TZ1.g
| Date | May 2022 | Marks available | [Maximum mark: 4] | Reference code | 22M.2.SL.TZ1.g |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Outline, State | Question number | g | Adapted from | N/A |
g.
[Maximum mark: 4]
22M.2.SL.TZ1.g
State the types of bonding in magnesium, oxygen and magnesium oxide, and how the valence electrons produce these types of bonding.
[4]
Markscheme
Award [1] for all bonding types correct.
Award [1] for each correct description.
Apply ECF for M2 only once.
Examiners report
About a quarter of the students gained full marks and probably a similar number gained no marks. Metallic bonding was the type that seemed least easily recognised and least easily described. Another common error was to explain ionic bonding in terms of attraction of ions rather than describing electron transfer.
Syllabus sections
Structure 2. Models of bonding and structure » Structure 2.2—The covalent model » Structure 2.2.1—A covalent bond is formed by the electrostatic attraction between a shared pair of electrons and the positively charged nuclei. The octet rule refers to the tendency of atoms to gain a valence shell with a total of 8 electrons. Deduce the Lewis formula of molecules and ions for up to four electron pairs on each atom.
Structure 2. Models of bonding and structure » Structure 2.1—The ionic model » Structure 2.1.1—When metal atoms lose electrons, they form positive ions called cations. When non-metal atoms gain electrons, they form negative ions called anions. Predict the charge of an ion from the electron configuration of the atom.