PHYSICAL - BONDING

Question 1

Describe ionic bonding and the factors that affect it

Answer 1

Metal and non -metal
Involves electrostatic attraction between oppositely charged ions in a lattice.
FACTORS = smaller ion (stronger attraction) and higher charge

Question 2

Define metallic bonding and its arrangement

Answer 2

electrostatic force of attraction between the positive metal ions and the delocalised electrons.
- arranged in a lattice

Question 3

What are the factors that affect the strength of metallic bonding

Answer 3

number of protons
number of delocalised electrons
size of ion (smaller the ion the stronger the bond)

Question 4

What are the types of covalent bond?

Answer 4

SINGLE (contains a shared pair of electrons)
MULTIPLE ( contains multiple pairs of electrons)
CO ORDINATE (contains a shared
pair of electrons with both electrons supplied by one atom) - uses an arrow

Question 5

How does a co-ordinate bond form?

Answer 5

When one atom has a lone pair of electrons that can be donated to an atom with a vacant orbital

Question 6

Which elements can expand their octet?

Answer 6

Aluminium Silicon Phosphorous Sulfur Chlorine Argon

Question 7

What is electronegativity?

Answer 7

The ability of an atom to attract the pairs of electron in a covalent bond.
It is based on the attraction of an electron pair and the nucleus of an atom

Question 8

3 factors that affect electronegativity

Answer 8

1. Size of the positive charge of the nucleus
2. Atomic radius
3. Shielding of nucleus

Question 9

What is a dipole?

Answer 9

A molecule or covalent bond that has a separation of charges

Question 10

How do dipoles occur?

Answer 10

When electrons are shared unequally between atoms in the same molecule due to a high difference in the electronegativity of the atoms involved

Question 11

What are two ways you can show a bond is polar

Answer 11

d+ and d-
Or an arrow with the head pointing towards more electronegative

Question 12

What does symmetrical mean

Answer 12

When the atoms are being pulled in the same direction

Question 13

Describe Van der Waals force

Answer 13

It is the weakest force and acts as an induced dipole between anything with electrons and creates temporary dipoles.

Question 14

What affects the strength of a van der waals force

Answer 14

1. Larger Mr means stronger IMF
2. Straight chain molecules experience stronger Van der Waals than branched chain molecules as they can line up and pack closer together which in turn reduces distance over which the force acts over and is therefore stronger.

Question 15

Van der waals melting and boiling point.

Answer 15

Boiling : The stronger the Van der Waals forces, the higher the boiling point
Melting : low melting points due to being a weak intermolecular force

Question 16

Describe a dipole-dipole force

Answer 16

Acts between molecules within a polar bond
The d+ and d- regions attract each other and hold the molecules together in a lattice like structure

Question 17

When do hydrogen bonds form

Answer 17

Forms between a hydrogen and a very electronegative atom (flourine, nitrogen and oxygen)
Electronegative atom must have a lone pair of electrons as these will be attracted to the partially charged hydrogen atom in another molecule and form the charge
Represented with a dashed line

Question 18

Hydrogen bonding melting and boiling points

Answer 18

Raises both melting and boiling points
- because h bonds are strong imf that create stable molecules and it takes more energy to break up to molecule than it would if the bond wasn’t there