DP Chemistry (last assessment 2024)

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Question 19M.2.hl.TZ2.c

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.2.hl.TZ2.c
Level hl Paper 2 Time zone TZ2
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 2]
19M.2.hl.TZ2.c

Dinitrogen monoxide, N2O, causes depletion of ozone in the stratosphere.

Explain why the first ionization energy of nitrogen is greater than both carbon and oxygen.

Nitrogen and carbon:

Nitrogen and oxygen:

[2]

Markscheme

Nitrogen and carbon:

N has greater nuclear charge/«one» more proton «and electrons both lost from singly filled p-orbitals»    [✔]

 

Nitrogen and oxygen:

O has a doubly filled «p-»orbital
OR
N has only singly occupied «p-»orbitals     [✔]

 

Note: Accept “greater e– - e- repulsion in O” or “lower e– - e- repulsion in N”.

Accept box annotation of electrons for M2.

Examiners report

Mixed responses here; the explanation of higher IE for N with respect to C was less well explained, though it should have been the easiest. It was good to see that most candidates could explain the difference in IE of N and O, either mentioning paired/unpaired electrons or drawing box diagrams.

Syllabus sections