DP Chemistry (last assessment 2024)

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Question 19M.2.hl.TZ2.3b(iii)

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.2.hl.TZ2.3b(iii)
Level hl Paper 2 Time zone TZ2
Command term Predict Question number b(iii) Adapted from N/A
b(iii).
[Maximum mark: 2]
19M.2.hl.TZ2.3b(iii)

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

Different sources of N2O have different ratios of 14N : 15N.

(b(iii))

Predict, giving two reasons, how the first ionization energy of 15N compares with that of 14N.

[2]

Markscheme

Any two:

same AND have same nuclear charge /number of protons/Zeff      [✔]

same AND neutrons do not affect attraction/ionization energy/Zeff
OR
same AND neutrons have no charge       [✔]

same AND same attraction for «outer» electrons     [✔]

same AND have same electronic configuration/shielding     [✔]

 

Note: Accept “almost the same”.

“Same” only needs to be stated once.

Examiners report

Many students realized that neutrons had no charge and could not affect IE significantly, but many others struggled a lot with this question since they considered that 15N would have a higher IE because they considered the greater mass of the nucleus would result in an increase of attraction of the electrons.

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