chemistry p1a

copper ispurifiedby electrolysis

electrolysis is used to obtain very pure metals.

the copper is cu2+ so is drawn to the cathode and sludge is left at the anode (not the copper)

when anatomloses or gains an electron

if a atom gains a electron like ahalogenwould it becomesnegativelycharged and is drawn towardspositivelycharged atoms.

there are

electrons who's mass is 1/200 electrons are negatively charged

neutrons who's mass is 1 areneutralhave no charge

and protons who's mass is also 1 arepositivelycharged

symbol name mass n.o atomic n.o electrons protons neutrons

na sodium 23 11 11 11 12

how to work out neutrons take away theatomicn.o from the mass n.o

covalent bonding is were instead of losing orgainingan aelectronthey share one

hydrogen has 1 electron so itsharesit with another hydrogen so they have a full shell

H2O does this O

sharesanelectron- H H-shares an electron

more reactive going up

halogens are poisones

chlorine kills bacteria (used in pools)

iodine'sand antiseptic

chlorine reacts withpotassiumiodideto form potassium chloridebecausechlorine is more reactive and the iodide gets displaced

aprecipitateis were to liquidsreactto for an insoluble solid (precipitate)

copper solution mixed with sodium hydroxide = blue

irom solution mixed with sodium hydroxide = sludgy red or sludgy green

zinc solution mixed with sodium hydroxide = white

sodium= yellow/orangeflame

potassium= liliac

calcium= brick red

copper= blue-green

hydration

something reacts with water to form a new thing

dehydration

turns something containing water into water and something

e.g carbohydrates into carbon and water