periodic tables Flashcards
why elements in same group same properties
same no. electrons in outer shel which they need to loose/gain
alkali metals physical properties
low mtp
less dense
soft
(unusual for metals)
alkali metals stored in oil
to not react with oxygen in the air
alkali metals no. electrons in outer shell
1
alkali metals observations reacting with water
Li - effervescence- moves on surface
Na - effervescence- moves on surface - melts into ball
K - effervescence- moves on surface - melts into ball - lilac flame
alkali metals react with water
metal + water > metal hydroxide (UI turns blue - alkali) + hydrogen (lit splint - squeaky pop)
alkali metals reactivity trend
loose outer shell electron when react
down G1 reactivity increases due to
- more shells - greater distance between nucleus + outer shell electron
- more shells - more shielding
so weaker EA between nucleus + outer shell electron so easier to loose electron
alkali metals reaction with oxygen
G1 metals are all white solids
metal + oxygen > metal oxide
alkali metals flame test
Li - red
Na - yellow
K - lilac
halogens
7 electrons in outer shell
react easily with metals to form ionic compounds form negative ions > HALIDES
exists as diatomic
halogen physical properties
go from gas to solid down G7
down G7 colour darker
down G7 mtp and bp increase
fluorine colour
pale yellow gas
pale yellow vapour
colourless (aq)
chlorine colour
pale green gas
pale green vapour
colourless (aq)
bromine colour
red-brown liquid
orange vapour
orange(aq)
iodine colour
dark grey solid
purple vapour
brown(aq)
halogens trend in mtp and bp
down G7 mtp and bp increase
- relative molecular mass increases
- intermolecular forces get stronger + harder to overcome
displacement reaction - chlorine and potassium bromide
chlorine displaces bromine
chlorine is more reactive
halogens reactivity trend
as you go down G7 reactivity decreases
- more shells - more distance between nucleus and outer shell
- more shells - more shielding
so weaker EA between nucleus and outer shell electron
harder to gain electron
redox reaction
a chemical reaction involving the transfer of one or more electrons from one reactant to another
(oxidation reduction reaction)
what happens in redox reaction
Cl2 + 2Br- > 2Cl- + Br2
Cl2 sharing electrons (covalent) and 2Br- has gained electrons (ionic)
Cl2 prefers to gain electrons not share so takes electrons from Br (more reactive)
now Br2 sharing electrons (covalent) and 2Cl- has gained electrons (ionic)
OILRIG
oxidation is loss reduction is gain
ionic equation
splint anything ionic and aqueous into ions cancel out spectator ions (same on both sides)
