bonding in all papers (3.1.3)

Question 1

whats a co-ordinate/dative bond?

Answer 1

a bond that contains a shared pair of electrons with both electrons supplied by one atom.

once formed is the same as any other covalent bond.

this is represented by an arrow.

Question 2

what are the 4 types of crystal structure?

Answer 2

• ionic
• metallic
• macromolecular ( giant
  covalent)
• simple molecular

Question 3

what are the properties of an ionic compound?

Answer 3

• high mpt and bpt
• strong electrostatic forces so a
  lot of energy is required to
  overcome.

Question 4

what are the properties of a simple molecular compound?

Answer 4

• less than 20 bonds
• covalently bonded molecules
  held together by weak van der
  waals forces.
• low mpt and bpt

Question 5

describe a linear molecule shape.

Answer 5

• 2 bonding pairs
• 0 lone pairs
• 180 bond angle
  Cl —– Be —– Cl

Question 6

describe a v-shaped molecule.

Answer 6

• 2 bond pairs
• 2 lone pairs
• 104.5 bond angle
  O
  / \
  H H

Question 7

describe a trigonal planar shaped molecule.

Answer 7

• 3 bond pairs
• 0 lone pairs
• 120 bond angle
  F
  |
  B
  / \
  F F

Question 8

describe a triangular pyramid shaped molecule.

Answer 8

• 3 bond pairs
• 1 lone pair
• 107 bond angle
  ..
  N
  / | \
  H H H

Question 9

describe a tetrahydral shaped molecule.

Answer 9

• 4 bond pairs
• 0 lone pairs
• 109.5 bond angle
  H
  |
  C
  / \ \
  H H H

Question 10

describe a trigonal bi-pyramid shaped molecule.

Answer 10

• 5 bond pairs
• 0 lone pairs
• 90 and 120 bond angles
  B B
  \ |
  B —- A —- B
  |
  B

Question 11

describe a octahedral shaped molecule.

Answer 11

• 6 bond pairs
• 0 lone pairs
• 90 bond angle
  F F F
  \ | /
  S
  / | \
  F F F

Question 12

describe a square planar shaped molecule.

Answer 12

• 4 bond angles
• 2 lone pairs
• 90 bond angle
  B B
  \ .. /
  A
  / .. \
  B B

Question 13

what are the different type of repulsions?

Answer 13

• lone pair, lone pair repulsion
  which is the greatest.
• lone pair, bond pair repulsion.
• bond pair, bond pair repulsion
  which is the lowest.

Question 14

what is bond polarity?

Answer 14

when the negative charge around a covalent bond isnt evenly spread around the orbitals of the bonded atoms.

Question 15

what is elecronegativity?

Answer 15

• the power of an atom to attract
  negative charge towards itself
  within a covalent bond.
• it increases along a period as
  atomic radius decreases and
  decreases down a group as
  shielding increases.

Question 16

what is a permanent dipole?

Answer 16

• exists between polar
  molecules.
• the more electronegative atom
  draws the negative charge
  towards itself.
• The greater the polarity of a
  bond or molecule, the stronger
  the permanent dipole-dipole
  interactions.
• can align to form a lattice of
  molecules similar to an ionic l
  lattice.

Question 17

what is an induced dipole?

Answer 17

• can form when the electron
  orbitals around a molecule are
  influenced by another charged
  particle.

A + B - A B
A + B - A+ B-

Question 18

name the different types of intermolecular forces?

Answer 18

• van der waals
• permanent dipole
• hydrogen bonds

Question 19

describe van der waals force.

Answer 19

• weakest type
• acts as an induced dipole
  between molecules.
• the larger the Mr, the stronger
  the intermolecular forces.
• straight chain molecules
  experience stronger van der
  waals forces than branched
  chain molecules as they can line
  up and pack closer together,
  reducing the distance over
  which the forces acts, therefore
  stronger.

Question 20

describe hydrogen bonding.

Answer 20

• strongest type
• only forms between hydrogen
  and the 3 worst most
  electronegative atoms:
  . nitrogen
  . oxygen
  . fluorine
  . the lone pair on these atoms
  forms a bond with a hydrogen
  atom from another molecule,
  shown with a dotted line.
• much hight mpt and bpt