Chemistry — Unit 1 — Test 1

25

90

80

15

IE(B) < IE(Be) and IE(O) < IE(N) due to subshell/shell stability effects.

IE decreases monotonically from Li to Ne with no exceptions.

IE(Be) < IE(B) because Be is to the left of B and trends dominate strictly.

IE(N) < IE(O) because O has greater nuclear charge, always increasing IE.

Fluorine, because it has the largest atomic radius among halogens.

Chlorine, because F–F repulsions in the compact 2p shell make adding e– to F less favorable.

Fluorine, because it is the most electronegative element in the periodic table.

Chlorine, because its 3p orbitals are higher in energy than F’s 2p orbitals.

Poor shielding by 5p electrons in Hf.

Relativistic expansion of s orbitals in Zr only.

Lanthanide contraction lowering the size of 5d elements.

d‑block expansion in the fourth period.

Be and Al (identical coordination chemistry).

Na and Ca (similar flame colors).

Li and Mg (e.g., formation of nitrides and covalent halides).

K and Sr (similar hydration energies).

All three scales are defined purely by atomic radii.

Pauling’s scale equals Mulliken’s numerically for all elements.

Allred–Rochow is based on polarizability only.

Pauling’s scale is bond‑energy based; Mulliken’s uses (IE + EA)/2; Allred–Rochow relates to electrostatic attraction on a valence electron.

Lanthanide expansion increasing bonding ability.

Dramatic increase in p‑character of bonding orbitals down the group.

Extra stability of half‑filled p subshell in Tl(I).

The inert‑pair effect (ns^2 electrons less inclined to participate in bonding).

MgO

CsF

LiF

BeI2

The d‑block has uniform radii across periods with no anomalies.

Poor shielding by 4f electrons causes lanthanide contraction that offsets the expected increase in size.

5d metals expand because of diffuse 5d orbitals, giving larger radii.

Relativistic contraction is significant only for 4d metals.