03: chem bonding

Question 1

ionic bonding

Answer 1

formation of ions involve a complete transfer of one or more electrons between atoms

ions in the compound are held together by strong electrostatic forces of attraction between oppositely charged ions

Question 2

magnitude of LE

Answer 2

LE proportional to (q+q-)/ (r+ + r-)
strength of ionic bond increases with greater ionic charge and smaller ions

Question 3

covalent bonding

Answer 3

a covalent bond is a electrostatic force of attraction between a shared pair of electrons and a positively charged nuclei to achieve octet

Question 4

metallic bonding

Answer 4

is a strong electrostatic force of attraction between the lattice of the positively charged metal cation and a sea of delocalised valence electrons

Question 5

factors affecting strength of covalent bond

Answer 5

1. bond order (1 pair, 2 pair)
2. bond length
3. bond polarity

Question 6

expanded octet

Answer 6

• only central non-metal atoms from period 3 onwards can expand their octet: due to ability to accommodate additional electrons using empty and energetically available d orbitals

Question 8

2bp, 2lp

Answer 8

linear, 180 degrees

Question 9

3bp, 0 lp
2bp, 1lp

Answer 9

trigonal planar, 120
bent, 118

Question 10

4bp, 0lp
3bp, 1lp
2bp, 2lp

Answer 10

tetrahedral, 109.5
trigonal pyramidal, 107
bent, 105

Question 11

5bp, 0lp
4bp, 1lp
3b, 2lp
2bp, 3lp

Answer 11

trigonal bipyramidal, 90, 120
see-saw, <90, <120
t-shaped, <90
linear, 180

Question 12

6bp, 0lp
5bp, 1lp
4bp, 2lp

Answer 12

octahedral, 90
square pyramidal, 90
square planar, 90

Question 13

pd-pd

Answer 13

positive end of one molecule’s dipole can attract the negative end of another molecule dipole

Question 14

hydrogen bonding

Answer 14

1. one molecule must have its H atom bonded to a highly electronegative atom (N, O, F)
2. the other molecule must have at least one lone pair on the highly electronegative atom

Question 15

consequence of hydrogen bonding

Answer 15

1. bp of HF> NH3
2. dimers
3. density of ice and water (causes ice have rigid tetrahedral structure, less closely packed, but in liquid state there is enough energy to overcome the hydrogen bonds)

Question 16

ion-dipole interactions

Answer 16

is the electrostatic forces of attraction between an ion and a polar molecule

Question 17

liquefication of gases

Answer 17

1. low temperatures
   at lower temperatures, molecules move at slower speed, bringing molecules closer together and resulting in the formation of intermolecular forces of attraction between molecules
2. high pressure
   molecules are pushed closer together and resulting in a formation of intermolecular FOA, molecule are eventually close enough to form liquid