Chemistry of the Elements

Question 1

What are the group 1 metals?

Answer 1

• the alkali metals

- all have one electron in their outermost shell, making them very reactive

Question 2

What happens when lithium, sodium and potassium react with water?

Answer 2

• they react more vigorously as you go down the group, produced a metal hydroxide solution that is alkaline
• also produces hydrogen
• lithium fizzes and moves slowly
• sodium moves rapidly, may ignite
• potassium burns with a lilac flame

Question 3

How does the rate of reaction change going down the group 1 metals?

Answer 3

• the elements become more reactive

Question 4

Why are elements with higher atomic number in group 1 more reactive?

Answer 4

• all group 1 metals have 1 electron in their outer shell
• as you go down group 1, the outermost electron is in a shell that’s further from the nucleus
• which means the attraction between the outermost electron and the nucleus becomes less
• so as you go down group 1, the atoms get bigger, the outer electron is more easily lost and the metals are more reactive

Question 5

What are group 7 elements called?

Answer 5

• halogens

Question 6

What are the properties of chlorine, bromine and iodine?

Answer 6

Chlorine:

• green
• gas at room temperature
• boiling point: -34 degrees celsius

bromine:

• red-brown
• liquid at room temperature
• boiling point: 59 degrees celsius

iodine:

• dark grey
• solid at room temp
• boiling point: 185 degrees celsius

Question 7

What happens as the atomic number of the halogens increase?

Answer 7

• the elements have a dark colour

- a higher boiling point

Question 8

Are the elements more reactive higher or lower in group 7 and why?

Answer 8

• the higher an element is, the more reactive it is

- the shell with the missing electron is nearer to the nucleus, so the pull from the positive nucleus is greater

Question 9

What forms when halogens combine with hydrogen?

Answer 9

• hydrogen halides

Question 10

What is hydrogen chloride?

Answer 10

• HCl

- gas at room temp

Question 11

What happens when hydrogen chloride is dissolved in water?

Answer 11

• the molecules split up into H+ ions and Cl0 ions
• a process called dissociation
• forming hydrochloric acid

Question 12

Why is hydrochloric acid acidic but not hydrogen chloride?

Answer 12

• it contains H+ ions

- you can test with blue litmus and it will turn red

Question 13

What if you dissolved HCl in methylbenzene?

Answer 13

• it does not dissociate, so it is not acidic

- blue litmus paper will stay blue, unless there is moisture on the paper or bottle

Question 14

What is a displacement reaction?

Answer 14

• a displacement reaction is where a more reactive element displaces (pushed out) a less reactive element from a compound

Question 15

What is a redox reaction?

Answer 15

• where oxidation and education happen at the same time

- displacement reactions are always redox reactions

Question 16

What is the oxidising agent?

Answer 16

• accepts electrons and gets reduced

Question 17

What is the reducing agent?

Answer 17

• donates electrons and gets oxidised

Question 18

Explain the relative reactivates of group 1 elements in terms of distance between outer electrons and the nucleus

Answer 18

• all group 1 metals have an electron in their outer shell
• as you go down group 1, the outermost electron is in a shell that’s further away from the nucleus
• so the attraction between the outermost electron and nucleus becomes less
• as you go down the group, atoms become baggers o outer electron is more easily lost and metals are more reactive