educake all

Question 1

What is seen when sodium is added to water but NOT seen when lithium is added to water?

Answer 1

melts into a ball bearing

Question 2

explain why potassium is more reactive than lithium (3 marks)

Answer 2

• potassium has more electron shells
• therefore outer electron is further from nucleus
• weaker/less electrostatic attraction/attractive forces between nucleus and outer electron
• therefore outer electron is lost more easily

Question 3

Is the outer electron in potassium more or less strongly attracted to the positive nucleus than the outer electron in sodium is?

Answer 3

less:
* The outer electron of potassium is further from the nucleus than it is for sodium
* This means that the electron is less strongly attracted to the nucleus and so it is more easily lost.

Question 4

True or false? A less reactive halogen will displace a more reactive halogen from an aqueous solution of its salt.

Answer 4

FALSE
A more reactive halogen will displace a less reactive halogen from an aqueous solution of its salt.

Question 5

describe the trend in boiling points of group 7 as you move up the group

Answer 5

As you move up the group of halogens, the molecules are smaller, so their boiling points decrease

Question 6

state the trend in reactivity of halogens, moving down group seven

Answer 6

reactivity decreases moving down the group

Question 7

when chlorine is added to sodium bromide solution, the mixture turns orange. What elements cause this orange colour?

Answer 7

bromine / displaced bromine

Question 8

state whether a reaction will take place when chlorine is added to porassium bromide. give a reason for your answer.

Answer 8

• yes, a reaction will take place
• chlorine will displace bromide from its compound
• because chloride ions are more reactive / are higher in the reactivity series than bromide ions

Question 9

when chlorine is added to sodium iodide what colour can be observed?

Answer 9

brown