inorganic/ periodic chem Flashcards
Group 2: trends in ionisation energy
Decreases as:
- more shielding so a weaker attraction to the nucleus
- distance from nucleus increases
- proton increase is overidden
Group 2: reactions with water
- Forms metal hydroxides
- Reactivity increases down group
*Mg reacts slowly in cold water but quicker in steam
Group 2: reaction with O(2)
white solids (oxides)
Group 2: Reactions with Cl(2)
Metal Chlorides
Group 2: trends in solubility
increases down a group (more alkaline)
Group 2: trends in sulfates and hydroxides solubility
sulfates: decreases down group
hydroxides: increases down group
Group 2: decomposition of carbonates
group 2 carbonates undergoing thermal decomposition forms: metal oxide & co2
group 2 carbonate thermal stability increases down the group:
- large electron cloud can be distorted when near 2+ ions so it’s less stable
Group 2: decomposition of nitrates
group 2 nitrates undergoing thermal decomposition forms: metal oxide & nitrogen dioxide & O2
Group 1: Decomposition
more stable than group 2
Group 1: Nitrate Decomposition
Nitrites + O2
Group 1: Testing Thermal stability of nitrates and carbonates
nitrates: glowing splint (o2) and brown gas (NO2)
carbonates: limewater + cloudy
testing for (+) ions
Calcium - red
Potassium - lilac
Sodium - yellow
Lithium - crimson
Rubidium - violet red
Caesium - blue
Barium - green
Testing Halides
add silver nitrate (nitric acid to remove carbonates)
cl =white
br = cream
i = yellow
add dilute ammonia
cl = dissolved
br = x
i = x
add conc ammonia
br = dissovled
i = x
What do the Halogens look like?
F2 = pale yellow gas
Cl2 = pale green gas
Br2 = brown liquid
I2 = grey solid
Halogens: trends in boiling points
increases as London forces increase
halogens: trends in electronegativity
decreases due to:
- more shielding
- increase distance between nucleus
halogens: reactions with water and ammonia
- white misty fumes
halogens + organic solvent
dissolve forming an organic layer
halogens + sulfuric acid
All make NaHSO4 + H(halogen)
HCl = white misty fumes
HBr + Br2 + SO2 = orange vapour (when reacted further)
HI + I2 +H2S + S= yellow solid and eggy smell (H2S)
Testing for sulfates
add HCl + Barium chloride forms:
- white precipitate (BaSO4)
- HCl removes presence of carbonate ions
Testing for Ammonium
add NaOH + heat forms:
ammonia gas/ turns red litmus blue
Testing for Hydroxides
turns red litmus blue
What reaction does bleach undergo?
disproportionation
2NaOH + Cl2 —-> NaClO + NaCl + H2O
hot alkali:
6NaOH + 3Cl2 —-> NaClO3 + 5NaCl + 3H2O
Water Sterilisation
1) H2O + Cl2 —> HCl + HClO
2) HClO + H20 —> ClO⁻ + H30⁺
