Elements of group 1 and 2

Question 1

Why does atomic radius increase down group 2?

Answer 1

Additional electron shells

Question 2

Why does reactivity increase down group 2?

Answer 2

Increased shielding and increased atomic radius means that the outer shell electron is easier to lose down the group

Question 3

Why does ionisation energy decrease down the group?

Answer 3

Greater atomic radius and increased shielding do easier to loser outer electron

Question 4

Generally how do the group 2 metals react with water?

Answer 4

reacts to produce a metal hydroxide and hydrogen

Question 5

What happens when magnesium reacts with steam?

Answer 5

reacts to form magnesium oxide and water

Question 6

What happens when group 2 metals react with chlorine gas?

Answer 6

react to from metal chlorides (white precipitate)

Question 7

What generally happens when group 2 metals react with oxygen

Answer 7

react to from the metal oxide

Question 8

What can happen when strontium or barium react with oxygen?

Answer 8

they react to from the metal peroxide

Question 9

Reaction of group 2 metals with dilute acid?

Answer 9

react to from salt and hydrogen

Question 10

Reaction of group 2 hydroxide with HCl?

Answer 10

chloride salt + water

Question 11

Reaction of group 2 hydroxide with H2SO4?

Answer 11

sulphate salt + water

Question 12

Reaction of group 2 hydroxide with HNO3?

Answer 12

Nitrate salt + water

Question 13

Trend of group 2 hydroxides solubility?

Answer 13

Increases down group - Mg(OH)2 least soluble Ba(OH)2 most soluble

Question 14

How is metal hydroxide used in medicine?

Answer 14

used in medicine as an antacid - neutralise acids as it is alkaline.

Question 15

Trend of group 2 sulphates solubility?

Answer 15

decreases down group - Mg(OH)2 most soluble Ba(OH)2 least soluble

Question 16

What happens when a group 2 metal carbonate
undergoes thermal decomposition?

Answer 16

produces carbon dioxide and a metal oxide

Question 17

What happens when a group 2 metal nitrate
undergoes thermal decomposition?

Answer 17

produces metal oxide, nitrogen dioxide and oxygen

Question 18

What happens to the heat required in thermal decomposition as the size of the ions increases?

Answer 18

The heat required increases.

Question 19

What happens when lithium nitrate undergoes thermal decomposition?

Answer 19

Lithium oxide + Nitrogen oxide + oxygen

Question 20

What happens when a group 1 metal undergoes thermal decomposition?

Answer 20

Metal nitrate + oxide

Question 21

Why is more heat required to carry out thermal decomposition in both group 1 and 2 carbonates and nitrates?

Answer 21

Smaller ions are more able to polarise the negative nitrate and carbonate ions more and break the c–O bond or the N–O bond.

Question 22

Describe procedure for flame test?

Answer 22

1. Take a nichrome wire and clean it by placing it into a solution of conc. HCl and then into a blue bunsen burner flame
   2.Repeat this cleaning until there is no colour produced in the flame
   3.Dip wire into unknown compound and place into flame. Observe the flame colour produced.

Question 23

Flame colour produced by Lithium?

Answer 23

Red

Question 24

Flame colour produced by Sodium?

Answer 24

Orange/yellow

Question 25

Flame colour produced by potassium?

Answer 25

lilac

Question 26

Flame colour produced by magnesium?

Answer 26

no colour

Question 27

Flame colour produced by calcium?

Answer 27

brick red

Question 28

Flame colour produced by strontium?

Answer 28

crimson red

Question 29

Flame colour produced by barium?

Answer 29

pale green

Question 30

Explain how colours are formed in flame tests?

Answer 30

-energy by flame absorbed by species
-some electrons promoted to higher energy orbitals
-When drop down release energy some in form of light
-Colour depends on wavelength of light
- some may release wavelengths that are not within the visible light spectrum