Paper 1 Flashcards
Trend in BP down halogens
More electrons
Strong LFs
More energy to break IMFs
BP increase
Define 1st ionisation energy
Renege required to remove 1 electron form each atom in 1 mol of gaseous atoms of an element to form 1 mole of gaseous 1+ ions.
E.g. Na(g) —> Na+ (g) + e^-
Define periodicity
Repeating trend in properties of elements across each period of periodic table
Strongest IMFs
LFs —> permanent dipole-dipole —> HBs
—increase in strength—>
How LFs brought about
Movement of electrons produce changing dipole
Instantaneous dipole will exist
And induce a dipole on neighbouring molecule
Which further induces dipole on neighbouring molecules and attract 1 another
Acid + metal carbonate
Salt + H2O + CO2
Acid + alkali
Salt + H2O
Acid + metal oxide/hydroxide
Salt + H2O
Ideal gas assumptions
No IMFs
Random motion
Elastic collisions
Negligible size
Hydrated salts assumptions
All H2O lost - heat to constant mass
No further decomposition
Define hydrated and water of crystallisation
H2O molecules are apart of crystalline structure
This water is known as water of crystallisation
Define relative atomic mass
Weighted mean mass of an atom of an element relative to 1/12th of mass of an atom of C-12
Define relative isotopic mass
Mass of isotope relative to 1/12th of mass of atom of C-12
Define isotope
Atoms of same element with different numbers of neutrons and different masses
Shape of p-orbitals
Dumb bell
Hold up to 1 or 2 electrons
3 p-orbitals
S-orbital
Sphere
Hold 1/2 electrons
She’ll number and electrons formula
n = shell number
2n^2
Define atomic orbital
Region around nucelus that can hold up to 2 electrons with OPP spins
Acid + metal
Salt + hydrogen
Define metallic bond
Strong electrostatic attraction between positive ions and delocalised electrons
Metallic bond properties
High electrical conductivity - delocalised electrons carry charge
High MP + BP - strong MB—> strong attraction
Giant metallic lattice
Don’t dissolve
Graphene and graphite
- 3 of 4 outer shell e-s used in CB
- remaining e- released into pool of delocalised e-s shred by all atoms in the structure
- good electrical conductors
- giant covalent structures of C
- planar hexagonal layers
- bond angle = 120* by electron-pair repulsion
graphene =
- single layer of graphite
- hexagonally arranged C atoms linked by strong CBs
graphite =
- parallel layers of hexagonally arranged C atoms
- layers bonded by weak LFs
- 3 of 4 outer shell e-s used in CB
- remaining e- released into pool of delocalised e-s shred by all atoms in the structure
what is the bond angle and structure of (carbon) Diamond?
tetrahedral arrangement - bond angle = 109.5* because of electron pair repulsion
why can’t silicon and carbon (diamond) conduct electricity?
in both structures, all 4 outer shell electrons are involved in CB, so none are available for conducting electricity.
C & Si
group 14 (4) - 4 electrons in their outer shell C (in diamond form) and Si use these 4 electrons to form CBs to other C/Si atoms
what is the structure and bonding of B, C and Si?
Giant covalent lattice - many billions of atoms are held together by a network of strong covalent bonds
Define 2nd ionisation energy
He+ (g) —> He2+(g) + e-
Energy required to remove 1 electron from each ion in 1 mol of gaseous 1+ ions of an element to form 1 mole of gaseous 2+ ions.
2nd ionisation energy explanation
After 1st electron lost, electron pulled closer to nucleus
Nuclear attraction increases + more IE needed to remove 2nd electron
Trend in IE down group
Atomic radius increases
More inner shell - increased shielding
Nuclear attraction on outer electrons decreases
1st IE decreases
Trend in IE across period
Nuclear charge increases
Same shell - similar shielding
Nuclear attraction increases
Atomic radius decreases
1st IE increases
Trend in reactivity of halogens
Atomic radius increases
More inner shells so shielding increases
Less nuclear attraction to capture an electron from another species
Reactivity decreases
Disproportionation reaction
Redox reaction in which same element is reduced and oxidised
Enthalpy change of formation
is the enthalpy change that takes place when one mole of a compound is formed from its elements under standard conditions, with all reactants and products in their standard states.
Enthalpy change of combustion
enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions, with all reactants and products in their standard states.
Enthalpy change of neutralisation
is the energy change that accompanies the reaction of an acid by a base to
form one mole of H.O(). under standard conditions, with all reactants and products in their standard states.
Buffer solution
Mixture of weak acid and its conjugate base which minimises changes in pH when small quantities of acid or alkali are added.
Define conjugate acid-base pair
Contains 2 species that can be interconverted by the transfer of a proton
Define a salt
The product of a reaction in which the H+ ions from the acid are replaced by metal or ammonium ions.
