chem 6 -noble gases halogens and alkali metals

properties of alkali metals

-soft

-loe density

-low melting point (decreases as you go down)

-reactivity increases as you go down

why are alkali metals very reactive

as you go down.outermost electron gets further away from nucleus=weaker forces of attraction=electrons is lost more esily

lithium + water

FIZZES steadily

sodium+water

melts into a ball and then fizzes quickly

pottasium + water

gives off sparks and hydrogen burns with lilac flame

alkali metal + water

metal hydroxide+hydrogen

alkali metal+chlorine

Metal chloride (salt)

alkali metal + oxygen

metal oxide

chlorine

yellow/green gas

bromine

red/brown liquid

iodine

grey solid

what do the halogens exist as

diatomic molecules

what happens to the melting point as you go down?

increases

chemical test for chlorine

-damp litmus paper is bleaches and turns white

what happens to the rectivity as you go down?

decreases

what do the halogens form when reacted with metal

-ionic compounds

-become metal halides -”ine” becomes “ide”

displacement reactions

-more reactive halogen replaces the less reactive one

why does the reactivity decrease as you go dwon

-more attractive force to pull in an extra electron,nut the force is already weak as the outermost shell is far from nucleus

why are noble gases inert

full outer shell = very stable

properties of noble gases

-inert=argon used aas a sheild gas in welding

-low density=helium used in balloons and airships

-non-flammability=argon,krypton and xenon inside light bulbs-stops filament burning away