group 7 halogens and noble gases

What are the properties of fluorine , chlorine , bromine and iodine ?

Fluorine- poisonous yellow gas (very reactive)

Chlorine-less reactive- poisonous dense green gas

Bromine- dense, poisonous brown volatile liquid or orange vapour

Iodine-dark grey solid that can form poisonous purple vapour

What do all the halogens exist as ?

Pairs of atoms called diatomic molecules

Each atom shares an electron to form a covalent bond

How do halogens react with non metals

Halogen atoms can share electrons through covalent bonding with other non metals to achieve a full outer shell

For example, hydrogen or carbon confirm compounds like hydrogen fluoride or carbon tetra chloride these compounds are known as simple molecular structures

For halogens How does the melting point and boiling point and the reactivity change as you go down the group

For halogens the melting and boiling point increases as you go down the group and the reactivity decreases

The reactivity decreases because as you go down the group the outer most shell gets further away from the positive nucleus . So the attractive force needed to pulll in an extra electron from atom gets weaker

And if halogen can’t attract electron to complete its outer shell then it can’t react. So larger atoms at the bottom of the table like iodine are least reactive

How do halogens form ionic bonds with metals ?

Halogens have 7 electrons on its outer shell when a halogen grains an electron to form 1- ion we call this a halide

And the name of the eleement / ion changes we add IDE on the end

E.g. chloride fluoride bromide

Halogens normally form ions with alkali metals e.g. sodium chloride

What happens in the displacement reaction ?

A more reactive halogen will always displace a less reactive halogen

Give an example of a displacement reaction with chlorine and bromine with potassium bromide

Bc chlorine is more reactive than bromine it displaces bromine and chlorine takes bromines place

Cl2(g) + 2kBr(aq) _ Br2(g)+ 2KCl (aq)

What are the properties of noble gases?

They exist as cloudless gases

Bc they have a full outer shell they are inert-meaning that they don’t react with anything , bc they don’t react with other atoms they exist as singular atoms and are also non flammable

How does the boiling point change as it goes down the group? For noble gases

The boiling point increases

For noble gases how does the atomic number change as u move down the group?

The atomic number increases said so the number of electrons increases . This causes the intermolecular forces betweeen the atoms to increase so more energy is needed to break them and so the boiling point increases