group 1 and 2 Flashcards
why is group II more polarising than group I
they have a smaller radius and higher charge
why does group I form more stable carbonates
larger ionic radius and smaller charge
metal + oxygen
metal oxide
metal + chloride
metal chloride
metal + water
hydroxide + hydrogen
acid + base
salt + water
oxide + water
hydroxide
oxide + acid
salt + water
trend of solubility descending group II sulphates
less soluble
trend of solubility descending group II hydroxides
more soluble
what factors increase polarising ability
high charge
small size
trend of thermal stability descending group I and II
increases
why do group I form more stable carbonates
larger ionic radius
smaller charge
nitrate ion
NO3 -
carbonate ion
CO3 2-
why do carbonates become more stable descending a group
larger ionic radius
why do carbonates decompose more readily with more polarising ions
higher charge
smaller radius
decomposition of a group II carbonate to a group II oxide process
smaller cation is more polarising and distorts the electron cloud of the carbonate anion
CO2 is given off, leaving the oxide
test for carbonate (of group I and II)
heat with blue flame
test gas given off with limewater
time how long limewater takes to go cloudy
apparatus for carbonate I and II test
test tube (carbonate) ->heated w bunsen
bung
delivery tube
test tube (limewater)
do group II nitrates decompose fully or partially
fully
products of group II nitrates decomposing (fully)
oxide + nitrogen dioxide + oxygen
do group I nitrates decompose fully or partially
partially
products of group I decomposition (partially)
nitrate(III)salt + oxygen
which group one nitrate decomposes fully (the exception)
lithium nitrate
experiment to test nitrates (group I and II)
nitrate in a heating test tube
heat with blue flame
note change in appearance of solid, time taken and wether NO2/O2 involved
colour of nitrogen dioxide gas
brown
test for oxygen gas
relights a glowing splint
identification of S block elements flame tests
clean nichrome wire by dipping in conc HCL and holding in blue bunsen flame
repeat until no colour is seen
dip rod in conc HCL then the solid
tip of wire in hottest part of bunsen flame and note the first colour
flame colour lithium
red
flame colour sodium
yellow/orange
flame colour potassium
lilac
flame colour rubidium
violet
flame colour caesium
violet
flame colour magnesium
colourless
flame colour calcium
yellow-red
flame colour strontium
red
flame colour barium
pale green
what causes the emission spectrum
electrons gain energy on heating and are promoted to a higher energy level shell
when returned to previous level they release the excess energy as light at a specific frequency
