Oxidation State

Question 1

When is an element said to be in a particular oxidation state?

Answer 1

when it has a specific oxidation number

Question 2

In a simple ion, what is the oxidation number?

Answer 2

the charge on the ion

Question 3

What are oxidation states greater than +4 more common in?

Answer 3

transition metals

Question 4

Where are high oxidation states found?

Answer 4

when the central metal ion is bound to an electronegative atom like oxygen

Question 5

What are the rules for working out oxidation states?

Answer 5

1. The oxidation number of an atom in an element is zero.
2. The oxidation number of an ion is equal to the charge on the ion.
3. The sum of the oxidation numbers of the atoms in an uncharged compound is zero.
4. The sum of the oxidation numbers of the atoms in a polyatomic ion equals the charge of the ion

Question 6

What do transition metals with differing oxidation numbers have?

Answer 6

Differing stabilities and different colours

Question 7

What do changes in the oxidation number of a transition metal involve?

Answer 7

loss or gain of electrons

Question 8

What is the general rule for metals with a high oxidation number?

Answer 8

they gain electrons and so act as oxidising agents.

Question 9

If the oxidation number decreases what does this indicate?

Answer 9

reduction

Question 10

What is the general rule for metals with a low oxidation number?

Answer 10

they lose electrons and so act as reducing agents

Question 11

If the oxidation number increases what does this indicate?

Answer 11

oxidation