module 3 Flashcards
(32 cards)
ca+O
CaO
Ca+H2O
Ca(OH)2+h2
metal + acid
salt + hydrogen
why does ionisation energy decrease down group 2
atomic radius increases and more shielding so less attraction between nucleus and outer electrons
CaO+H2O
Ca(OH)2
solubility down group 2
increases
ph of solution down group 2
increases, more alkaline
group 2 agriculture
calcium hydroxide Ca(OH)2 is added to fields as lime by farmers to increase ph of acidic soils
boiling point down group 7
bp increases as there are more electrons,stronger London forces, more energy required to break intermolecular forces
fluorine
pale yellow gas
chlorine
pale green gas
bromine
red/brown liquid
iodine
shiny grey solid
astatine
black solid
solid sample has never been seen
halogen halide displacement reaction
add solution if each halogen to aqueous solution of other halides.
to tell them apart add non polar solvent like cyclohexane
reactivity down group 7
reactivity decreases as atomic radius increases, more shielding, less nuclear attraction to capture electron from a mother species
disproportionation reaction
a reaction in which the same element is both oxidised and reduced
2 examples of disproportionation reaction
chlorine with water and chlorine with dilute sodium hydroxide
Cl2+h2O
HClO+HCl
cl2+NaOH
NaClO+NaCl+H2O
NaClO is used as
bleach
cl- in aqueous sol
pale green/colourless
Br- in aqueous sol
yellow
I- in aqueous sol
Brown
