Group 2

Question 1

Why are group 2 metals in the S- Block of the periodic table

Answer 1

All Group II elements have their highest 2 electrons in ‘s’ sub shells

Question 2

Why does the 2nd ionisation energy of a group 2 metal decrease down the group?

Answer 2

Number of protons increase

Atomic radii increases going down the group these highest energy electrons are held further out from the nucleus.

The Group II elements increase in size going down the group so there is more shielding from inner shells

so less energy is needed to overcome the attraction between the nucleus and the outer 2 electrons.

Question 3

Explain why calcium has a higher melting point than barium

Answer 3

Descending Group II the ions get bigger. This means there is weaker attraction between the sea of delocalised electrons and the metal cations, the metallic bonds are weaker descending the group and are more easily overcome. Therefore the melting point decreases going down the group

Question 4

Why are group 2 elements always oxidised

Answer 4

they lose their 2 outer e-

Question 5

Reactions with LIQUID Water

Answer 5

Reactions with water become more violent as the group is descended.

Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g)
- Mg(OH)2 indigestion remedy to neutralise stomach acid

Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g)

Question 6

Reactions with Steam

Answer 6

Mg(s) + H2O(l) → MgO(s) + H2(g)
-reacts vigorously

MgO = white solid
bright white light

Question 7

Solubilities of Group 2 Hydroxides and Sulfates

Answer 7

Question 8

Uses of Barium Sulfate – BaSO4

Answer 8

good at absorbing X rays. ‘Barium Meal’. A barium meal, X-rays are absorbed and an image of the organs can be obtained.

Barium Sulfate is highly toxic. However safe because it is so insoluble it cannot dissolve

Question 9

Testing for Sulfate Ions – SO42

Answer 9

Add BaCl2
White precipitate
Sulfate ions present as barium sulfate has been produced.
Ba2+(aq) + SO42-(aq) → BaSO4(s)

Question 10

Magnesium chloride can be used to test for the present of which negative ions?

Answer 10

OH-
forms Mg(OH)2

Question 11

What is observed when MgCl2 is added to NaOH?

Answer 11

white ppt

Question 12

State the trend in reactivity with water down group 2

Answer 12

Reactivity increases

Question 13

What group 2 trend increase down the group?

Answer 13

Atomic radius

Question 14

What type of bonding do all group 2 elements have?

Answer 14

Metallic

Question 15

What is observed when Ba reacts with water?

Answer 15

A colourless solution and effervescence (fizzing)