EL8

Question 1

What are some characteristics of s-block metals?

Answer 1

• soft
• weak
• low melting points
• very reactive with water and oxygen

Question 2

Can the s-block metals be found naturally in their elemental form?

Answer 2

No because they are too reactive.

Question 3

What is the first ionisation enthalpy?

Answer 3

The energy needed to remove one electron from every atom (in one mole of isolated gaseous atoms of the element).

Question 4

What is general equation for the first ionisation process?

Answer 4

X(g) → X+(g) + e-

Question 5

Which electron does the ionisation remove?

Answer 5

One of the outer shell electrons

Question 6

Which elements have high first ionisation enthalpies?

Answer 6

Group 0 elements - as they are difficult to ionise and are very unreactive.

Question 7

Which elements have low first ionisation enthalpies?

Answer 7

Group 1

Question 8

Why does the first ionisation enthalpy decrease as you go down a group?

Answer 8

• More filled shells of electrons between outermost electron and nucleus.
• These shield the nucleus from the outermost electron
• This decreases the attraction between nucleus and outermost electron.
• So it is easier to remove the outermost electron

Question 9

What does second, third, fourth etc ionisation enthalpies mean?

Answer 9

Energy required to remove one electron.

Question 10

What is the general equation for the second, third, fourth etc ionisation processes?

Answer 10

X+(g) → X2+(g) + e-

X2+(g) → X3+(g) + e- (and so on)

Question 11

What is the formula for group 1 metal oxides?

Answer 11

M2O

Question 12

What is the general equation for the reaction of group 2 elements with oxygen?

Answer 12

2M(s) + O2(g) → 2MO(s)

Question 13

What is the general equation for the reaction of group 2 elements with water?

Answer 13

M(s) + 2H2O → M(OH)2(aq) + H2(g)

Question 14

What is the general equation for the decomposition of group 2 carbonates?

Answer 14

MCO3(s) → MO(s) + CO2(g)

Question 15

What is the trend for the decomposition of group 2 carbonates?

Answer 15

The carbonates become more difficult to decompose down the group.

Question 16

How does thermal stability change in group 2?

Answer 16

Thermal stability increases down the group.

Question 17

What is charge density?

Answer 17

A measure of the concentration of charge on the cation.

Question 18

Why does thermal stability change in group 2?

Answer 18

• The smaller the 2+ ion, the higher the charge density.
• Cations with a higher charge density can polarise the negative charge around the carbonate ion.
• This makes it less stable and easier to break up when heated.

Question 19

What is the trend in reactivity of group 2 metals with water?

Answer 19

Increases down the group

Question 20

What is the trend in thermal stability of group 2 carbonates?

Answer 20

Decomposes at increasingly higher temperatures down the group.

Question 21

What is the trend in pH of group 2 hydroxides in water?

Answer 21

pH increases down the group

Question 22

What is the trend in solubility of group 2 hydroxides?

Answer 22

Solubility increases down the group

Question 23

What is the trend in solubility of group 2 carbonates?

Answer 23

Solubility decreases down the group