IB Chemistry HL 3.1 Periodicity Question Bank

Group: (elements in vertical) columns in periodic table and Period: (elements in horizontal) rows in periodic table; Allow elements in same group have similar chemical properties and within a period, atoms have same number of shells/energy levels (but number of electrons in valence/outer shell increases).

Marking guidance:

Allow groups distributed vertically and periods distributed horizontally / OWTTE.
Allow group number gives number of valence/outer shell electrons (for main

group elements) and period gives same number of shells/energy levels.

$\mathrm{Co}^{2+}$;

Marking guidance:

Accept +2, 2+, cobalt(II), II.

partially filled/incomplete d subshell/sub-level/orbitals; d orbitals split (into two sets of different energies);
(colour due to) electron transition between (split) d orbitals / d to d transitions / frequencies of visible light absorbed by electrons moving from lower to higher d levels ;
colour due to remaining frequencies / complementary colour seen; Allow wavelength as well as frequency.

$$\mathrm{O}_{2}(aq)+4e^{-}+2\mathrm{H}_{2}\mathrm{O}(l) \rightarrow 4\mathrm{OH}^{-}(aq)$$

Oxidation numbers:




Award [2] for five correct and [1] for four correct.
Accept use of oxidation states 0,+1,-2,-2,+1.
Penalize once for incorrect notation, such as 2 or 2-.

groups indicate the number of electrons in the highest energy level/outer/valence shell;
periods indicate the number of (occupied) energy levels/shells (in the atom);

$\quad \mathrm{V}_{2} \mathrm{O}_{5}$ catalyses oxidation of $\mathrm{SO}_{2} / \mathrm{V}_{2} \mathrm{O}_{5}$ is a catalyst in the Contact Process; Fe catalyses the reaction between $\mathrm{N}_{2}$ and $\mathrm{H}_{2} / \mathrm{Fe}$ is a catalyst in the Haber Process; Ni / Pd / Pt catalyses hydrogenation / manufacture of margarine / addition of hydrogen to C=C / conversion of alkenes to alkanes;
Pd / Pt is a catalyst in catalytic converters / Pd / Pt catalyzes reaction of $\mathrm{NO}_{2}$ and $\mathrm{CO} / \mathrm{NO}_{2}$ and (unburnt) fuel/exhaust gases; Accept other correct examples.

Marking guidance:

Accept formulas or names of substances.

Any two of: forms acidic oxides «rather than basic oxides» forms covalent/bonds compounds «with other non-metals» forms anions «rather than cations» behaves as an oxidizing agent «rather than a reducing agent»

Marking guidance:

Award [1 max] for 2 correct nonchemical properties such as nonconductor, high ionisation energy, high electronegativity, low electron affinity if no marks for chemical properties are awarded.