Chapter 8 - Reactivity trends

Question 1

Are group two elements reducing or oxidising agents?

Answer 1

Reducing agents

Question 2

Why does reactivity increase down the group in group 2?

Answer 2

The atoms react by loosing 2 electrons to form 2+ ions. The atomic radius increases down the group as well as shielding. This means that the attraction between the nucleus and the outer shell electrons decreases down the group, so they can be lost more easily

Question 3

Does boiling point increase or decrease down the group in group 7?

Answer 3

Increases

Question 4

What is the trend in appearance of elements in group 7 as you go down the group?

Answer 4

They get darker in colour and go from gas to solid

Question 5

What is the appearance of bromine at room temperature?

Answer 5

Red/brown liquid

Question 6

What is the appearance of iodine at room temperature?

Answer 6

grey solid

Question 7

What is the appearance of chlorine at room temperature?

Answer 7

pale green gas

Question 8

Predict the appearance of astatine at room temp

Answer 8

black solid

Question 9

Are halogens (group 7) oxidising or reducing agents?

Answer 9

Oxidising agents

Question 10

Why does the reactivity of the halogens (group 7) decrease down the group?

Answer 10

Halogens react by gaining one electron to form 1- ions. As you go down the group it is harder to gain an electron as the atomic radius increases, there is more shielding and so there is less nuclear attraction meaning it is harder to gain an electron

Question 11

What is disproportionation?

Answer 11

A redox reaction where the same element is both oxidised and reduced

Question 12

How do you test for halide ions?

Answer 12

-Add a few drops of dilute nitric acid, and then a few drops of silver nitrate solution
-Different colour precipitates will form depending on the halides present:
chloride ions give a white precipitate of silver chloride
bromide ions give a cream precipitate of silver bromide
iodide ions give a yellow precipitate of silver iodide