4.1: Reactivity of metals

Question 1

What is the difference between oxidation and reduction?

Answer 1

● Known​ ​as​ ​oxidation​ ​reactions​ ​because​ ​the​ ​metals​ ​gain​ ​oxygen
● Reduction=​ ​loss​ ​of​ ​oxygen​ ​&​ ​oxidation=​ ​gain​ ​of​ ​oxygen

Question 2

What is the reactivity series?

Answer 2

● Reactivity​ ​of​ ​a​ ​metal​ ​is​ ​related​ ​to​ ​its​ ​tendency​ ​to​ ​form​ ​positive​ ​ions
● Metals​ ​can​ ​be​ ​arranged​ ​in​ ​order​ ​of​ ​their​ ​reactivity​ ​in​ ​a​ ​reactivity​ ​series
o Metals​ ​potassium,​ ​sodium,​ ​lithium,​ ​calcium,​ ​
magnesium,​ ​zinc,​ ​iron​ ​and copper​ ​can​ ​be​ ​put​ ​in​ ​
order​ ​of​ ​their​ ​reactivity​ ​from​ ​their​ ​reactions​ ​with
water​ ​and​ ​dilute​ ​acids

Question 3

How can we extract metals through reduction?

Answer 3

● Gold,​ ​since​ ​it​ ​is​ ​very​ ​unreactive,​ ​it​ ​is​ ​found​ ​in​ ​the​ ​Earth​ ​as​ ​the​ ​metal​ ​itself
● But,​ ​most​ ​metals​ ​are​ ​found​ ​as​ ​compounds​ ​that​ ​require​ ​chemical​ ​reactions​ ​to extract​ ​the​ ​metal
● Metals​ ​less​ ​reactive​ ​than​ ​carbon​ ​can​ ​be​ ​extracted​ ​from​ ​their​ ​oxides​ ​by​ ​reduction with​ ​carbon
o Don’t​ ​forget:​ ​reduction​ ​involves​ ​the​ ​loss​ ​of​ ​oxygen

Question 4

What does OIL RIG stand for?

Answer 4

It​ ​stands​ ​for​ ​​O​xidation​ ​​I​s​ ​​L​oss​ ​and R​eduction​ ​​I​s​ ​​G​ain​ ​(of​ ​electrons)

Question 5

What is a half-equation?

Answer 5

A half equation is used to represent what happens when atoms or ions gain or lose electrons. In half equations:
-electrons are shown as e-
-the numbers of atoms of each element must be
the same on both sides
-the total charge on each side must be the same
(usually zero)

Question 5

What is a half-equation?

Answer 5

A half equation is used to represent what happens when atoms or ions gain or lose electrons. In half equations:
-electrons are shown as e-
-the numbers of atoms of each element must be
the same on both sides
-the total charge on each side must be the same
(usually zero)

Question 6

Balance the half equation for the formation of aluminium during electrolysis: Al3+ + e- → Al.

Answer 6

The balanced half equation is: Al3+ + 3e- → Al (because three negatively charged electrons are needed to balance the three positive charges on the aluminium ion).

Question 7

What are some important things to remember when writing a balanced ionic equation?

Answer 7

In a balanced ionic equation:
-the number of positive and negative charges on
each side of the arrow are the same
-the numbers of atoms on each side of the arrow
are the same

Question 8

Balance this ionic equation:

Ag+(aq) + CO32-(aq) → Ag2CO3(s)

Answer 8

2Ag+(aq) + CO32-(aq) → Ag2CO3(s)