Topic 2: Bonding And Structure

Question 1

Ionic bonding definition

Answer 1

The electrostatic forces of attraction between oppositely charged ions

Question 2

features of ionic compounds

Answer 2

• giant ionic structure
• most ionic compounds dissolve in water
• conduct electricity when molten
• have high melting points due to many electrostatic forces of attraction

Question 3

what happens to the melting point of ionic compounds as size of charge on the ions increases

Answer 3

Bigger charge, stronger forces of attraction so more energy is required to overcome so higher melting point.

Question 4

what happens to the strength of ionic bonds as size of ion decreases

Answer 4

Smaller ion, stronger electrostatic forces of attraction/stronger ionic bonding

Question 5

Describe and explain trend in ionic radius moving down a group

Answer 5

• ionic radius increases down group
• number of electron shells increases so ionic radius increases

Question 6

Features of graphite

Answer 6

• conducts electricity due to delocalised electrons
• high melting point due to strong covalent bonds
• insoluble due to covalent bonds being too strong to break
• layers slide easily due to weak intermolecular forces

Question 7

Features of diamond

Answer 7

• rigid arrangement allows heat to conduct well
• very high melting point due to very strong covalent bonds
• doesn’t conduct electricity due to no delocalised electrons
• insoluble due to covalent bonds being too strong

Question 8

Covalent bonding definition

Answer 8

The electrostatic forces of attraction between the shared electrons and positive nuclei

Question 9

Dative covalent bonding

Answer 9

Both electrons come from one atom. 2 electrons donated to form a bond.

Question 10

Name of shape with 2 bonding pairs and 0 lone pairs

Answer 10

Linear. Angle 180 degrees.

Question 11

Name of shape with 3 bonding pairs and 0 lone pairs

Answer 11

Trigonal planar. Angle 120 degrees.

Question 12

Name of shape with 4 bonding pairs and 0 lone pairs

Answer 12

Tetrahedral. Angle 109.5 degrees

Question 13

Name of shape with 5 bonding pairs and 0 lone pairs

Answer 13

Trigonal bipyramidal. Angle 90 & 120 degrees.

Question 14

Name of shape with 6 bonding pairs and 0 lone pairs

Answer 14

Octahedral. Angle 90 degrees.

Question 15

Name of shape with 3 bonding pairs and 1 lone pair

Answer 15

Trigonal pyramidal. Angle 107 degrees.

Question 16

Name of shape with 2 bonding pairs and 2 lone pairs

Answer 16

Bent. Angle 104.5 degrees.

Question 17

Name of shape with 5 bonding pairs and 1 lone pair

Answer 17

Square pyramidal. Angle < 90 degrees.

Question 18

Name of shape with 4 bonding pairs and 2 lone pairs

Answer 18

Square planar. Angle 90 degrees.

Question 19

Metallic bonding definition

Answer 19

The electrostatic forces of attraction between a metal cation and a ‘sea’ of delocalised electrons

Question 20

Electronegativity definition

Answer 20

The ability for an atom to attract electrons towards itself in covalent bonds

Question 21

Put the intermolecular forces in order from weakest to strongest

Answer 21

London forces<permanent dipole-dipole<hydrogen bonding

Question 22

What happens to the solubility the longer a hydrocarbon gets

Answer 22

Longer hydrocarbon less soluble - stronger london forces between hydrocarbons as longer non-polar chain so greatly outweigh intermolecular forces between hydrocarbon and water.

Question 23

Compare the amount of London forces between longer, straight hydrocarbons and branched hydrocarbons

Answer 23

Longer, straight hydrocarbons have more London forces (because more points of contact) so more energy is needed to overcome the forces and the boiling point increases. Branched hydrocarbons cant pack together so there are less (and weaker) London forces and lowers the boiling point.

Question 24

Contrast the ionic radius between isoelectronic ions

Answer 24

Ionic radius in isolectronic ions decreases as atomic number increases

Question 25

NCl3 has a higher boiling point than NF3. Why?

Answer 25

1. Greater london forces in NCl3
2. because NCl3 has more electrons than NF3
3. Both have permanent dipole-dipole forces and dipole forces stronger in NF3
4. Because F more electronegative than Cl
5. London forces are most significant intermolecular force so more energy needed to overcome intermolecular forces between NCl3 than NF3

Question 26

What is an orbital

Answer 26

A region/space in an atom in which there is a high probability of finding electrons of which can hold a maximum of 2 electrons with opposite spin