Materials from molecules

Question 1

Molecule

Answer 1

A discrete group of atoms of known formula, bonded together

Question 2

Lattice

Answer 2

Atoms bonded together in a continuous 3D structure

Question 3

Intramolecular forces

Answer 3

bonds between non metal atoms which form molecules

Question 4

Intermolecular forces

Answer 4

Bonds between molecules

Question 5

Localised electrons

Answer 5

Shared electrons in a covalent bond which are found between the nuclei

Question 6

VSEPR theory

Answer 6

Valence shell electron pair repulsion theory
Negatively charged electron pairs in the outer shell of an atom repel each other and are therefore placed as far away from each other as possible

Question 7

Intermolecular forces strength

Answer 7

weaker than strong forms of bonding such as ionic, metallic and covalent bonds

Question 8

when a substance is melted/vaporised

Answer 8

weak intermolecular forces are broken

Question 9

Non polarised covalent bond

Answer 9

Equal distribution of valence electrons

no charge on either side of the bond (no net dipole)

Question 10

Polarised covalent bond

Answer 10

Electrons will stay closer to the most electronegative atom which has a stronger pull on the electrons in the bond
created two oppositely charged poles- partial positive charge, partial negative charge

Question 11

Level of polarity

Answer 11

Depends on the difference between the electronegativities

greater the difference, greater the polarity of the molecule

Question 12

Non-polar molecules

Answer 12

Partial charges are evenly distributed around the molecule
Individual dipoles of the covalent bonds cancel each other out perfectly
no overall dipole

Question 13

Polar molecules

Answer 13

Partial charges are unevenly distributed around the molecule

results in a net dipole

Question 14

Strength order of intermolecular forces

Answer 14

H-bonding
Dipole-dipole
dispersion

Question 15

Dipole-dipole

Answer 15

polar molecules
Attraction between the partial negative/positive ends of the polar molecules
more polar a molecule is, stronger the dipole-dipole forces

Question 16

H-bonding

Answer 16

occurs in molecules where a hydrogen atom is covalently bonded to a FON atom
partial positive charge of hydrogen is attracted to lone pairs of electrons in FON atoms of neighbouring molecules

Question 17

Dispersion forces

Answer 17

Caused by temporary dipoles
result of random movement of electrons surrounding molecules which cause instantaneous dipoles
always present between molecules
Strength increases as Mr of molecule increases. Larger molecules have a larger number of electrons.
In larger molecules, dispersion forces can dominate over dipole-dipole forces

Question 18

Non metal properties

Answer 18

Soft
Low MP and BP
Don’t conduct electricity in molten or solid state

Question 19

Non metals soft

Answer 19

Intermolecular forces are weak

Bonds can be readily broken and substance is easily crushed or moulded

Question 20

Non metals low MP and BP

Answer 20

weak forces of attraction between particles

Question 21

Non metals dont conduct electricity

Answer 21

no free moving charged particles in either state