The Periodic Table

6 marks · Normal

This question is about the relationship between electronic configuration, position in the Periodic Table, and chemical behaviour.

(a)

State why all the elements in Group 2 have similar chemical reactions.

[2 marks]

(b)

Helium and argon are both found in Group 0 (noble gases) of the Periodic Table.

(i)

State the electronic configuration of argon.

[1 mark]

(ii)

Explain why the elements in Group 0 are so unreactive.

[2 marks]

(c)

Iron (Fe) and sulfur (S) are both in Period 4. Based on their position in the Periodic Table, state which is the metal and which is the non-metal.

[1 mark]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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(a) They have the same number of electrons in their outer shell (2), so react in similar ways.

(b(i)) 2,8,8

(b(ii)) Because they have a full outer shell (helium has 2, others have 8), so do not lose or gain electrons and are very stable.

Common mistakes: Not linking outer electrons to chemical similarity; Incorrect electronic configuration for argon; Not mentioning full outer shell or stability for inertness; Confusing metal/non-metal for iron and sulfur

Show mark scheme and worked solution

Marking points

M1 (a) · 1 mark · Links group similarity to same outer electrons or shell.

A1 (a) · 1 mark · Gives correct detail (2 electrons in outer shell / reacts similarly).

B1 (b(i)) · 1 mark · Correctly gives argon's electronic configuration as 2,8,8.

M2 (b(ii)) · 1 mark · Mentions full outer shell or stability.

A2 (b(ii)) · 1 mark · Fully explains that this causes low reactivity.

B2 (c) · 1 mark · Correctly states iron is a metal and sulfur a non-metal.

Worked solution

a: All Group 2 elements have 2 electrons in their outer shell, so their reactions are similar.

b(i): Argon's configuration is 2,8,8.

b(ii): Group 0 elements are unreactive because their outer shell is full (so they do not tend to gain or lose electrons).

c: Iron is a metal since it's on the left of Period 4; sulfur is a non-metal, on the right.