Group-7 (phy Differences, Explain Reactivty And Displacement)

Question 1

Give a brief description of group 7

Answer 1

They are called halogens and have 7 electrons in the outer shell. They make halogen molecules cl2 and halide ions cl*. The reactivity decreases as you go down

Question 2

Explain the trend in reactivity

Answer 2

Decreased reactivity going down the group
This is because an electron need it be gained in the outer shell. In chlorine the outer shell is closer to the nucleus than bromine. The nucleus of chlorine has greater attraction. For the outer electron then bromine so chlorine will gain more easily

Question 3

What are group 7 called ?

Answer 3

Halogens and they are all non metals

Question 4

How do group 7 elements exist ?

Answer 4

They overlap their outer shell electrons and share a pair of electrons with a same element meaning they are covalanelty bonded

They are all diatomic

Question 5

How do the melting and boiling point change going down the group ?

Answer 5

Melting and boiling point increase as we move down group 7
So elements like Fluorine and chlorine will exist as a gas but bromine would exist as a liquid

Question 6

How do group 7 react with other non metals ?

Answer 6

They form covalent compounds

Question 7

How do group 7 react with metals ?

Answer 7

From ionic compounds

Question 8

How do group 7 change going down the group ?

Answer 8

Less reactive
Gains electrons less easily
Greater shielding of outer electron
Increased boiling and melting point

Question 9

What is a key fact you should know ?

Answer 9

A more reactive halogen can displace a less reactive half on from an aqueous solution of its salt

Meaning

Sodium bromide + fluorine —- sodium fluoride + bromine

This is because fluorine has displaced bromine due to it being more reactive