U1-3-1 - Electronic Configuration and Oxidation States

Question 1

Which two transition metals are exceptions to the Aufbau principle?

Answer 1

Chromium, [Ar] 4s¹ 3d⁵

Copper, [Ar] 4s¹ 3d¹⁰

Question 2

Why do chromium and copper adopt 3d⁵ and 3d¹⁰ configurations?

Answer 2

Special stability associated with half-filled and full 3d subshell.

Question 3

Which electrons are lost first when transition metals form ions?

Answer 3

4s electrons

Question 4

Why is valency 2 common in transition metals?

Answer 4

Loss of two 4s electrons.

Question 5

Oxidation state/number

Answer 5

Valency equivalent. Can include charge.

E.g. II, +2, 2 all the same.

Question 6

Oxidation state of oxygen

Answer 6

–2

Question 7

Oxidation state of halogens

Answer 7

–1

Question 8

Oxidation state of group 1 metals

Answer 8

+1

Question 9

How can you predict if an oxidation state is stable?

Answer 9

If its electronic configuration is stable, the oxidation state is also stable.

Question 10

Oxidation can be defined as an ___________ in oxidation number.

Answer 10

increase

(e.g. +2 to +3)

Question 11

Reduction can be considered as a ___________ in oxidation number.

Answer 11

decrease

(e.g. +2 to 0)

Question 12

Compounds with metals in _______ oxidation states tend to be oxidising agents.

Answer 12

high

(e.g. +5)

Question 13

Compounds with metals in high oxidation states tend to be __________ agents.

Answer 13

oxidising

will more readily accept electrons due to +ve charge

Question 14

Compounds with metals in _____ oxidation states tend to be reducing agents.

Answer 14

low

(e.g. +2)

Question 15

Compounds with metals in low oxidation states tend to be __________ agents.

Answer 15

reducing

can donate more (d) electrons due to low ox. st.