DP Chemistry (last assessment 2024)

Test builder »

Question 18N.2.sl.TZ0.4

Select a Test
Date November 2018 Marks available [Maximum mark: 5] Reference code 18N.2.sl.TZ0.4
Level sl Paper 2 Time zone TZ0
Command term Explain, State Question number 4 Adapted from N/A
4.
[Maximum mark: 5]
18N.2.sl.TZ0.4

Properties of elements and their compounds can be related to the position of the elements in the periodic table.

(a)

Explain the decrease in atomic radius from Na to Cl.

[2]

Markscheme

nuclear charge/number of protons/Zeff increases «causing a stronger pull on the outer electrons» ✔

same number of shells/«outer» energy level/shielding ✔

 

Accept “atomic number” for “number of protons”.

(b.i)

Explain why the radius of the sodium ion, Na+, is smaller than the radius of the oxide ion, O2−.

[2]

Markscheme

isoelectronic/same electronic configuration/«both» have 2.8 ✔

more protons in Na+ ✔

(b.ii)

State a physical property of sodium oxide.

[1]

Markscheme

Any one of:
brittle ✔
high melting point/crystalline/solid «at room temperature» ✔
low volatility ✔
conducts electricity when molten ✔
does not conduct electricity at room temperature ✔

 

Do not accept soluble in water.

Ignore any chemical properties.

Syllabus sections