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Define ionic bonding
Electrostatic attraction between two oppositely charged ions
Describe the effects that ionic radius and ionic charge have on the strength of ionic bonding
The shorter the distance between oppositely charged ions and the higher the charges, the stronger the electrostatic forces between them.
How are ions formed
Positive ions from through the loss of electrons and negative ions form through the gain of electrons
Describe the trend of ionic radii down the groups
The radii increases as there are more shells
Describe the trend of ionic radii with isoelectronic ions
The greater the number of protons the smaller the atomic radii as the electrons are pulled more closely to the nucleus
Describe the evidence for the existence of ions
This is shown through x-ray diffraction as the electron density maps show the likelihood of finding electrons in a region
Define covalent bond
Strong electrostatic attraction between two nuclei and the shared pair of electrons between them
Describe the relationship between bond length and strength
Generally, the shorter the bond, the stronger it is
How is the shape of a simple molecule determined?
This occurs by electron pair repulsion
State the main shapes of molecules and their angles
Little - 180°
TurniPs - 120°
Never - 104.5°
Punch - 107°
Tiny - 109.5°
TriBes - 90° and 120°
Over - 90°
How do lone pairs affect bond angles
Each lone pair will reduce the bond angle by 2.5°
Define elctronegativity
The ability of an atom to attract the bonding electrons in a covalent bond
State the ranges of the electronegativity scale and the bonding it corresponds to
0 - 0.4 = non-polar covalent
0.4 - 1.7 = polar covalent (permanent dipole)
1.7 - 4 = ionic bond
When will molecules be non polar
When they have an electronegativity between 0 and 0.4 and are symmetrical
Describe London forces
forces
Describe permanent dipole forces
1. Occurs between polar molecules
2. It is stronger than London forces, so have higher b.p
3. They occur in asymmetrical molecules and have a bond with significant difference in electronegativity
Describe hydrogen bonding
1. Occurs with an H and a N/O/F which are the most electronegative and have a lone pair of electrons
2. There is a 180° between two molecules bonded by hydrogen bonds
3. Occurs in addition to London forces
Describe H2O, NH3 and HF in terms of their hydrogen bonds
1
Explain the two anomalous properties of water
1. High m.p and b.p- have both London (dipole-dipole) and hydrogen bonds
2. Ice has a lower density that water- when the hydrogen bonds are broken as the ice melts, the water molecules get closer together
Explain the trends in boiling temperatures of the hydrogen halides
HF → HI → HBR → HCl
This is due to the increasing electronegativity, meaning that HF can form hydrogen bonds while the others can’t
Where are giant lattices present
1. Ionic solids (giant ionic lattices)
2. Covalently bonded solids (giant covalent lattices)
3. Solid metals (giant metallic lattices)
What is the structure of iodine and water
They are simple molecular
Describe the structure of graphite
1. It is macromolecular
2. 3 covalent bonds per atom
3. Delocalised electrons between layers
Describe the structure of diamonds
1. Macromolecular
2. Tetrahedral structure
3. 4 covalent bonds per atom
Describe the structure of graphene
1. One layer of graphite
2. 3 covalent bonds per atom
Define enthalpy change of formation
Enthalpy change when 1 mole of substance is formed from its constituent elements in their standard states under standard conditions
Define 1st ionisation energies
Heat energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous +1 ions
Define 2nd ionisation energies
Heat energy required to remove 1 mole of electrons from 1 mole of gaseous +1 ions to form 1 mole of gaseous +2 ions
Define lattice formation energy
The enthalpy change when one mole of an ionic lattice is formed from its isolated gaseous ions
Define enthalpy of atomisation
The enthalpy change when one mole of atoms is formed from its its element in its standard state under standard conditions
Define 1st electron affinity
The enthalpy change when one mole of gaseous atoms acquires one mole of electrons to form one mole of gaseous negative ions (EXO)
Define 2nd electron affinity
The enthalpy change when one mole of gaseous negative ions acquires one mole of electrons to form one mole of gaseous 2- ions (ENDO)
State the steps of the Born-Haber process
1. Atomise metal
2. Ionise metal
3. Atomise non metal
4. Electron affinitise non metal
5. Lattice
fAt Ion At EaLing
Note 
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