CHEMISRTY ( group 1 and group 7 )

list all elemants from group 1

lithium,sodium,potassium,rubidium,caesium,francium.

Describe the reactivity of group 1 metals?

Reactivity increases as we go down group 1

Describe the properties of alkalai metals in group 1

• soft ( easy to cut with knife )

• highly reactive

• low density

• low melting/boiling point

• good conductor of electricity

• shiny when cut

Why does reactivity increase?

Reactivy increases as we go down group 1 because, the radius of the atom increases. This means that it has greater distance between the positive nucleus and the negative outer electron. This means that it is easier to lose the electron as it is closer to the other electrons from the other atoms, making it less attracted to the positive nucleus so reactivity increases.

example, sodium is more reactive than lithium. This is because sodium has 8 more electrons than lithium which only has 3. This makes the radius of the atom bigger, creating a bigger distance between the positive nucleus and negative electron on the outer shell, making it easier to lose one electron compared to lithium losing one electron, so reactivity inccreases.

List all elemants in group 7

fluorine,chlorine,bromine,iodine

Describe the reactivity in group 7 halogens?

Reactivity decreases as you go down the group 7

Describe the properties of group 7 halogens

• conduct no electricity

• all toxic and harmful in high concentrations

• each has a distinctive colour

• boiling points increase as u go down the group

Why does reactivity decrease as u go down group 7?

Reactivity decreases as you go down group 7. All halogens in group 7 have 7 electrons on their outer shell, which means it is relatively easy for them to gain 1 more electron to become stable. However, as u go down group 7, the radius of the atom increases, making the outer shell further away from the positive nucleus, weakening the attract to gain 1 more electron, so it is harder.

Example; fluorine is more reactive than chlorine. This is because, fluorine has 9 electrons and chlorine has 17. This means that fluorine’s electron configuration is: 2,7 and chlorines is : 2,8,7

This shows that fluorines electrons have a less radius between the outer shell of electrons and the posistive nucleus.Fluorine’s nucleus has a stronger pull on the incoming electron

Because the distance is shorter and there’s less shielding from inner electrons compared to chlorines electrons, so we can predict that reactivity will decrease as you go down.