Group 2 alkaline earth metals

Question 1

All group 2 elements are…

Answer 1

metals

Question 2

What happens down the atomic radius for group 2?

Answer 2

-down group 2 atomic radius increases
-due to more filled shells
-so outer electron is further from the nucleus

Question 3

What happens to ionisation energy down group 2?

Answer 3

-ionisation energy decreases down group 2 due to greater atomic radius
-and greater shielding
-therefore the outer electron is attracted less strongly, so less energy is required to remove an electron

Question 4

What happens to melting point down group 2?

Answer 4

-melting point generally decreases down group 2 due to increased ionic radii so decrease in charge/size ratio of the ion
-so weaker metallic bonding
-so less energy required to break the metallic bonds

Question 5

Discuss how magnesium reacts with water

Answer 5

-reacts very very slowly with cold water
-reacts readily with steam

Question 6

What is the word and symbol equation for the reaction of magnesium and steam?

Answer 6

magnesium + steam —> magnesium oxide + hydrogen

Mg(s) +H2O (g) —> MgO(s) + H2(g)

Question 7

How can you describe MgO(s)?

Answer 7

white solid

Question 8

How do calcium, strontium, and barium all react with cold water?

Answer 8

vigorously

Question 9

What is the word and symbol equation for calcium and cold water?

Answer 9

calcium + water —> calcium hydroxide + hydrogen

Ca(s) +2H2O (l) —> Ca(OH)2 (aq) + H2(g)

Question 10

What is the observations when magnesium reacts with steam?

Answer 10

magnesium reacts with steam when heated :
-glows orange
-white solid MgO(s) formed

Question 11

Discuss Ca(OH)2 in water and what it can be used for

Answer 11

Ca(OH)2 is only sparingly soluble in water, is also called limewater. tests for CO2 gas

Question 12

What is the observation when calcium reacts with water?

Answer 12

cloudy white mixture formed

Question 13

What is the word and symbol equation for the reaction of strontium and water?

Answer 13

strontium + water —> strontium hydroxide + hydrogen

Sr(s) + 2H2O(l) —> Sr(OH)2 (aq) + H2(g)

Question 14

What is the observation when strontium reacts with water and why?

Answer 14

Sr(OH)2 is more soluble than Ca(OH)2 in water so a colourless solution is formed

Question 15

What is the word and symbol equation for the reaction of barium and water?

Answer 15

barium + water —> barium hydroxide + hydrogen

Ba(s) + 2H20(l) —> Ba(OH)2 (aq) + H2(g)

Question 16

What is the observation when barium reacts with water?

Answer 16

Ba(OH)2 is the most soluble of group 2 so a colourless solution is formed

Question 17

The more soluble the hydroxide, the stronger the…

Answer 17

alkali, as a higher concentration of hydroxide ions

Question 18

What can Mg(OH) be used for?

Answer 18

in medicine as indigestion cure/antacid, and as a laxative to relieve constipation
-is a weak alkali
-neutralises excess stomach acid but isn’t corrosive or toxic

Question 19

What is Ca(OH)2 used for?

Answer 19

by farmers in agriculture to add to soils to increase pH, neutralise acidic soils