The Halogens

Question 1

What group are the halogens?

Answer 1

7

Question 2

Properties of the halogens

Answer 2

-low melting and boiling points
-acid when dissolved in water

Question 3

As you go down group 7, what are the trends?

Answer 3

-melting point increases
-reactivity decreases

Question 4

Why does reactivity decrease as you go down group 7?

Answer 4

As you go down group 1 the reactivity decreases as the outer shell is further away from the nucleus and so the electron being gained on the outer shell feels less attraction to the positive nucleus and so it is a lot harder to gain the electron

Question 5

When halogens react, what charge ion do they become?

Answer 5

-1 ion as they gain an electron

Question 6

Chlorine reacting with hydrogen symbol equation

Answer 6

H2 + Cl2 —> 2HCl

Question 7

Test for chlorine gas

Answer 7

Bleaches damp blue litmus paper white and turns it red in between as chlorine gas is acidic

Question 8

What are formed when halogens react with metals?

Answer 8

Metal halides

Question 9

What are displacement reactions?

Answer 9

A more reactive halogen can displace a less reactive halogen from its salt. These are examples of redox reactions (Cl2 + 2Br^- —> 2Cl^- + Br2)

Question 10

Displacement reaction examples

Answer 10

Cl2 + NaCl = no reaction
Cl2 + NaBr = reacts (yellow/orange)
Cl2 + NaI = reacts (orange/brown)

Br2 + NaCl = no reaction (yellow/orange
Br2 + NaBr = no reaction
Br2 + NaI = reacts (orange/brown)

I2 + NaCl = no reaction (orange/brown)
I2 + NaBr = no reaction (orange/brown)
I2 + NaI = no reaction