Grup 2 and 7

Question 1

Describe the solubility trend of hydroxides as you go down the group and list their solubility

Answer 1

Increases going down group two.
Mg(OH)2– sparingly soluble
Ca(OH)2– sparingly soluble
Sr(OH)2– more soluble
Ba(OH)2– completely dissolves

Question 2

Describe the solubility of sulphates going down the group and list their solubility

Answer 2

Solubility decreases down the group
MgSO4– completely dissolved
CaSO4– fairly soluble
SrSO4– sparingly soluble
BaSO4– insoluble

Question 3

Describe the test for sulfate ions- SO4

Answer 3

Add BaCl2, forms white precipitate. Sulfate ions present as barium sulfate has been produced

Question 4

Flourine electronegativity and observation

Answer 4

F-F covalent bond is weak. Atom is very small meaning that the non- bonding pairs of electrons are held so close that they start to repel. 4.0- pale yellow gas

Question 5

Appearance and electronegativity of Cl

Answer 5

Pale green, 3.0

Question 6

Appearance and electronegativity of Br

Answer 6

Yellow brown or if non polar- orange/ brown. 2.8

Question 7

Iodine

Answer 7

Brown, non polar- purple, solid- black. 2.5

Question 8

Describe the trend in atomic radius as you go down the group- provide reason

Answer 8

Atomic radius increases due to more shielding, further from the nucleus meaning a weaker nuclear attraction on outer electrons

Question 9

Describe the trend in atomic radius as you go down the group- provide reason

Answer 9

Atomic radius increases due to more shielding, further from the nucleus meaning a weaker nuclear attraction on outer electrons

Question 10

Describe the trend in ionisation energies as you go down group 2

Answer 10

Decreases: Atomic radius gets bigger, further from the nucleus, weaker nucleus attraction on outer electrons

Question 11

Describe the trend in ionisation energies as you go down group 2

Answer 11

Decreases: Atomic radius gets bigger, further from the nucleus, weaker nucleus attraction on outer electrons

Question 12

Describe the trend in melting point as you go down group 2

Answer 12

Decreases: Ionic size increases, lower charge density so weaker attraction on delocalised electrons

Question 13

Describe the trend in melting point as you go down group 2

Answer 13

Decreases: Ionic size increases, lower charge density so weaker attraction on delocalised electrons

Question 14

Which substances form white precipitate

Answer 14

Mg(OH)2 and BaSO4

Question 15

Test for sulfate:

Answer 15

BaCl2 + sample. A positive result shows a white precipitate

Question 16

Test for hydroxides:

Answer 16

NaOH and metal ion. Positive test= white precipitate

Question 17

What is Mg(OH)2 used for

Answer 17

Treating indigestion (milk of magnesia)

Question 18

What is barium sulfate used for

Answer 18

Taking x -ray images of the stomach. Insoluble so doesn’t dissolve

Question 19

Describe the change in state down group 7

Answer 19

Melting point and boiling point increases, van der waals get stronger between molecules. All simple molecules require more energy to break

Question 20

Describe the electronegativity down group 7

Answer 20

Decreases, atom radius increases, shielding increases, nuclear attraction on pair of electrons gets weaker