3 Redox I

Question 1

Define “oxidation”

Answer 1

Gain of oxygen or removal of hydrogen/electrons

Question 2

Define “reduction”

Answer 2

Gain of hydrogen/electrons or removal of oxygen

Question 3

Define “redox”

Answer 3

When reduction and oxidation take place

Question 4

How does electronegativity changes within different elements?

Answer 4

Electronegativity increases across a period and decreases down a group

Question 5

When would hydrogen not have an oxidation state of +1?

Answer 5

As atoms and molecules (0) or hydride ion in metal hydrides (-1)

Question 6

When would oxygen not have an oxidation state of -2?

Answer 6

As atoms and molecules (0), in hydrogen peroxide (-1) or in F₂O (+2)

Question 7

When would fluorine not have an oxidation state of -1?

Answer 7

As atoms and molecules (0)

Question 8

How do metals behave in redox?

Answer 8

• have positive values in compounds
• value is usually that of the Group No.
• several possibilities the values go no higher than the Group No.

Question 9

How do non-metals behave in redox?

Answer 9

• mostly negative based on their usual ion
• can have values up to their Group No.

Question 10

Define “disproportionation reaction”

Answer 10

A reaction in which an element in a single species is being simultaneously oxidised and reduced