Module 3 - Periodic table and energy

Cards (71)

  • Le Chatilier's principle:
    in dynamic equilibrium if there is a change in conditions, equilibrium shifts to counteract the change
  • Equilibrium: increase of concentration of reactants
    • equilibrium shifts right
    • increases forward reaction
    • decreasing reactants and increasing products
  • Equilibrium: decrease of concentration of reactants
    • equilibrium shifts left
    • increasing the reverse reaction
    • increasing reactants and decreasing products
  • Equilibrium: decrease in concentration of products
    • equilibrium shifts right
    • increase forward reaction
    • increasing products and decreasing reactants
  • Equilibrium: increase of concentration of products
    • equilibrium shifts left
    • increasing reversed reaction
    • decreasing products and increasing reactants
  • Equilibrium: increase in temperature
    • equilibrium shifts to reduce the temperature
    • favours endothermic reaction
  • Equilibrium: decrease in temperature
    • equilibrium shifts to increase the temperature
    • favours exothermic reaction
  • Equilibrium: increase in pressure
    • equilibrium shifts to favour less gas mole
  • Equilibrium: decrease in pressure
    • equilibrium shifts to favour more gas mole
  • Equilibrium: catalysts
    • catalysts have no effect on equilibrium as both forward and reverse reactions are increased equally
  • mendeleev's periodic table:
    • 60 known elements
    • arranged in atomic mass
    • left gaps for undiscovered elements
  • today's periodic table:
    • arranged in atomic number
    • groups - vertical columns
    • periods - horizontal vows
  • electron configuration:
    • same-grouped elements have the same no of electrons in the outer shell
    • same grouped elements have the same no of electrons in sub-shells
  • ionisation energy:
    • the ability to lose an electron from an atom to form a positive ion
  • first ionisation energy:
    • the energy required to remove 1 electron in each atom from 1 mole of gaseous atoms to form 1 mole of 1+ gaseous ions
  • factors affecting ionisation energies:
    • nuclear charge - more protons more attraction
    • atomic radius - closer distance more attraction
    • electron shielding - less shells more attraction
  • successive ionisation energies
    • depends on electrons in the outer shell
    • once outer shell in removed ionisation energy increases
    • due to less shielding and small atomic radius
  • trends in ionisation energies - N to O drop
    • in oxygen in the p-orbital electrons start to pair up so due to repulsion its easier to remove 1 electron
  • trends in ionisation energy: Be to B drop
    • boron has a p-orbital while beryllium doesn't, so boron has a higher energy so it is easier to remove
  • metallic bonding:
    • strong electrostatic attraction between cation and delocalised electrons due to opposite poles
    • is a giant metallic lattice structure
  • metallic bonding properties
    • conductivity - in solids and liquids delocalised electron carry charge
    • points - high as lots of energy needed to overcome electrostatic attractions
    • solubility - doesn't dissolve as a reaction will take place no dissolving
  • giant covalent bonding:
    • simple molecular lattice - N, O, S, P, F, Cl - weak London forces
    • giant covalent lattice - C, B, Si - strong covalent bonds
  • Diamond + Silicon conductivity
    • all 4 electrons are bonded to the carbon so there are no delocalised electrons to carry charge
    Graphite conductivity
    • only 3 are bonded to carbon so 1 delocalised electron to carry charge
  • Group 2:
    • metals are very reactive and do not occur in elemental from so naturally found in stable compounds
  • Group 2 REDOX reactions:
    • metal + oxygen = metal oxide
    • metal + water = metal hydroxide + hydrogen
    • metal + acid = salt + hydrogen
  • Group 2 trends:
    • reactivity increases - more shielding and a larger atomic radius
    • solubility of hydroxides increases - due to more hydroxide ions
  • group 2 uses:
    • bases - can neutralise acids
    • agriculture - calcium hydroxide increases soil pH to neutralise acid in soil to produce water
    • medicine - magnesium and calcium tablets treat acid indigestion
  • Halogens:
    • non-metals which are very reactive and do not occur in their elemental form
  • Group 7 reactions:
    • redox - oxidising agents as it causes other species to lose electrons
    • displacement - non-metals displace each other depending on halide reactivity
  • Group 7 trends:
    • boiling point increases - more electrons, more London forces more energy required to break
    • reactivity decreases - large atomic radius, more shielding and less nuclear attraction
  • colour analysis on group 7s in water
    • chlorine - pale green
    • bromine - orange
    • iodine - brown
  • colour analysis on group 7s in cyclohexane
    • chlorine - pale green later
    • bromine - orange layer
    • iodine - violet layer
  • qualitative analysis: carbonate test
    • add nitric acid - bubbles formed
    • test if CO2 run through lime water to from white precipitate
  • qualitative analysis: sulfate test
    • add barium nitrate - white precipitate forms
  • qualitative analysis: halide test
    • add silver nitrate
    chlorine - white, bromine - cream, iodine - yellow
    • to see clear results add ammonia
  • in qualitative analysis: the order
    • carbonate
    • sulfate
    • halide
    • ammonium
  • qualitative analysis: ammonium test
    • add sodium hydroxide
    • add damp red litmus paper - turns blue
  • in qualitative analysis: why this order
    • carbonate - sulfate or halides don't produce bubbles
    • sulfate - carbonates will form a white precipitate
    • halide - carbonates and sulfates will from precipitates
  • enthalpy - the measure of heat lost and gained in a chemical reaction
  • enthalpy change equation:
    • H(products) - H(reactants)