IB Docs (2) Team MC test: Periodic trends
Multiple choice test on 3.2 Periodic trends
Use the following 'quiz' to test your knowledge and understanding of this sub-topic. You will need access to a periodic table (Section 6 of the IB data booklet).
If you get an answer wrong, read through the explanation carefully to learn from your mistakes.
Which oxide is amphoteric?
Al2O3 is amphoteric as it can behave either as an acid when it reacts with sodium hydroxide or as a base when it reacts with hydrochloric acid.
Which of the following trends decrease down group 1 from Li → Cs?
I. melting point
II. ionization energy
III. atomic radius
The atomic radius increases from Li to Cs as the outer electrons get further from the nucleus.
Which of the following trends increase down group 17 from F → I?
I. ionization energy
II. melting point
III. anionic radius
The ionization energy decreases as electrons are being removed from higher energy levels which are further from the nucleus as the group is descended.
Which is the largest ion?
They all contain 18 electrons but P contains the smallest number of protons in its nucleus so will attract the electrons less strongly than the other nuclei.
Which is the least electronegative element?
F is the most electronegative. The alkali metals are the least electronegative (most electropositive) and they become more electropositive upon descending the group.
Which statement explains why atomic radii decrease across a period?
As more electrons are added to the same main energy level protons are added to the nucleus which attracts the level closer to the nucleus.
The first ionization energies for four consecutive elements in the periodic table are 1681, 2081 and 496 and 738 kJ mol-1 respectively. Which elements have these values?
The first two are increasing then there is a large decrease which means the outer electron of the third element is in a higher new main energy level.
Which oxides can react with water to form acidic solutions?
I. SiO2
II. SO2
III. P4O10
They are all acidic oxides but SiO2 does not react with water; it only reacts as an acid when heated strongly with sodium hydroxide.
Which row correctly states the units of electron affinity and electronegativity (based on Pauling's scale)?
| Row | Units of electron affinity | Units of electronegativity |
| 1 | Does not have units | kJ mol-1 |
| 2 | kJ mol-1 | kJ mol-1 |
| 3 | kJ mol-1 | Does not have units |
| 4 | Does not have units | Does not have units |
Pauling's scale of electronegativity is a relative measure of the attraction that an atom has for a shared pair of electrons. Electron affinity refers to the energy change when an electron is added to an isolated atom in the gaseous state, X(g) + e−→ X−(g).
Which order is correct when the size of atoms and ions are compared?
Positive ions are always smaller than the atom from which they are derived. Br > Cl as its main outer energy level is further from the nucleus. O− (9 electrons, 8 protons) is larger than O (8 electrons, 8 protons) but O2− (10 electrons, 8 protons) is even larger than O− as it contains one more electron.
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