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properties of alkali metals

properties of alkali metals

low melting points

low boiling points

low density

very reactive

what is produced when alkali metals react with water

metal hydroxide + hydrogen

as you go down group 7, the melting and boiling points…

increase

what are the properties of chlorine, bromine and iodine and room temperature?

chlorine - green gas

bromine - brown/red liquid

iodine - grey solid

does reactivity increase or decrease as you go down for halogens?

decrease

halogens react with alkali metal to form

salts

what happens to the MP, BP and density of noble gases as you move down?

they increase

typical properties of transition metals

• strong, hard and shiny

• high densities

• high melting points

• good catalysts

• colourful

• fairly unreactive

• more than one ion

test for carbon dioxide

• bubble it through limewater

• will turn cloudy if carbon dioxide is present

test for hydrogen

• use a lit splint

• place it in a test tube full of the gas

• if it makes a ‘squeaky pop’ hydrogen is present

test for oxygen

• take a glowing splint and place in test tube

• if it relights, oxygen is present

test for chlorine

• hold a piece of damp blue litmus paper over the test tube

• if the gas is chlorine, it will bleach the litmus paper to white

test for halide ions

• add dilute nitric acid

• add a few drops of silver nitrate solution

• chloride will give a white precipitate

• bromine will give a cream precipitate

• iodide will give a yellow precipitate

test for carbonate ions

• add some barium chloride solution

• if there are carbon ions present - a white precipitate of barium carbonate will form

• then add some dilute hydrochloric acid

• the presence of carbonate ions will cause the mixture to fizz, as the carbonate will react with the acid to form CO2

• collect the gas and bubble it through limewater, it should turn cloudy

• after all the barium carbon has reacted, you’ll end up with a colourless solution containing Ba2+ ions

test for sulphate ions

• add barium chloride solution

• a white precipitate will form if sulphate ions are present

• add some dilute hydrochloric acid

• the barium sulphate should not react with the hydrochloric acid

flame test colour for lithium

crimson red

flame test colour for sodium

yellow

flame test colour for potassium

lilac

flame test colour for calcium

brick red

flame test colour for copper

blue-green

sodium hydroxide solution for calcium

white

sodium hydroxide solution for copper

blue

sodium hydroxide solution for iron (II)

green

sodium hydroxide solution for iron (III)

brown

sodium hydroxide solution for zinc

white at first, but then redissolves in excess NaOH to a colourless solution