DP Chemistry (last assessment 2024)

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Question 21M.2.hl.TZ2.2a(ii)

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Date May 2021 Marks available [Maximum mark: 2] Reference code 21M.2.hl.TZ2.2a(ii)
Level hl Paper 2 Time zone TZ2
Command term Explain Question number a(ii) Adapted from N/A
a(ii).
[Maximum mark: 2]
21M.2.hl.TZ2.2a(ii)

The properties of elements can be predicted from their position in the periodic table.

(a(ii))

Explain why the first ionization energy of sulfur is lower than that of phosphorus.

[2]

Markscheme

P has «three» unpaired electrons in 3p sub-level AND S has one full 3p orbital «and two 3p orbitals with unpaired electrons»
OR
P: [Ne]3s23px13py13pz1 AND S: [Ne]3s23px23py13pz1


Accept orbital diagrams for 3p sub-level for M1. Ignore other orbitals or sub-levels.

 

repulsion between paired electrons in sulfur «and therefore easier to remove» ✓


Accept “removing electron from S gives more stable half-filled sub-level" for M2.