transition metals electron configuration

Question 1

Copper is one of the few period 4 transition metals to form a +1 oxidation state. Explain why in terms of its electron configuration

Answer 1

Cu [Ar] 4s1 3d10
Has 1 electron in the 4s sub-shell that can be lost. Most transition metals have 2

Question 2

Write the full electron configuration for Sc and Sc3+
The definition of a transition metal is that it forms at least 1 stable ion with an incomplete d sub-shell. Use this to explain why Sc does not have typical properties of a transition metal

Answer 2

Sc [Ar] 4s2 3d1

Sc3+ [Ar] 4s0 3d0
Does not form an ion with an incomplete d sub-shell

Question 3

Write the full electron configuration for Fe2+ and Fe3+. Use these to predict and explain which oxidation state of iron is more stable

Answer 3

Fe2+ [Ar] 4s0 3d6

Fe3+ [Ar] 4s0 3d5

Fe3+ has a half filled d sub-shell (no electrons are paired in an orbital) this is more stable

Question 4

Zinc only forms a Zn2+ ion and is resistant to further reduction. Explain why in terms of its electron configuration

Answer 4

Zn2+ [Ar] 4s0 3d10
Completely filled 3d sub-shell is more stable

Question 5

Zinc does not form coloured compounds. Explain why in terms of its electron configuration

Answer 5

Requires a partially filled 3d sub-shell (to absorb photons in the visible part of the spectrum). Zn has 3d10 electron configuration (full)