(A) Topic 3 - Bonding

Question 1

What is an Ionic Bond?

Answer 1

A strong electrostatic attraction between oppositely charged ions.

(Consists of a metal and a non-metal)

Question 2

What increases the strength of an Ionic Bond?

Answer 2

1. Greater charge on the ions
2. Smaller ions

Question 3

What are the properties of an Ionic Compound?

(Include Mp/Bp, conductivity, strength and solubility)

Answer 3

• High melting points and boiling points - strong electrostatic attraction between oppositely charged ions which is hard to break.
• Electrical conductivity as a liquid or dissolved in solution but not as a solid - the ions must be able to move freely.
• Brittle - lattice of alternating charges
• Soluble - Contains charges so interacts with polar water molecules

Question 4

What is a metallic bond?

Answer 4

The strong electrostatic attraction between the lattice structure of positively charged metal ions and the sea of delocalised electrons.

Question 5

What increases the strength of metallic bonding?

Answer 5

• Smaller metal ion size
• Greater charge on the ion
• Greater number of delocalsied electrons

Question 6

What are the properties of a metallic bonds?

(Include Mp/Bp, conductivity, strength and solubility)

Answer 6

• High melting points and boiling points due to strong electrostatic forces of attraction between positve ions and sea of delocalised electrons
• High conductivity - voltage is carried by the sea of delocalised electrons
• Mallaeble due to the layers of ions which can slide over each other but strong due to electrostatic forces of attraction
• Insoluble in water - as ions do not interact with polar molecules

Question 7

What is a covalent bond?

Answer 7

When two atoms share electrons to obtain a full outer shell, forming a strong electrostatic attraction between the shared pair of electrons and the nucleuses.

(Occurs between two non-metals)

Question 8

What increases the strength of a covalent bond?

Answer 8

• Shorter bonds (usually)
• More bonds, e.g. double is stronger than single, and triple is stronger than double.

Question 9

What are the different types of covalent bonding?

Answer 9

• Simple Molecular
• Coordinate
• Giant Covalent e.g. Diamond, Graphite, Graphene, Silicon Dioxide

Question 10

What is a coordinate bond?

(practice drawing one)

Answer 10

A covalent bond where both of the electrons come from the same species

(check in booklet)

Question 11

What are the properties of giant covalent structures, e.g. Diamond?

(Include Mp/Bp, conductivity, strength and solubility)

Answer 11

• Melting and Boiling points are very high due strong covalent bonds that require lots of energy to break
• Unconductive - all electrons are in fixed orbitals and there are no charged ions.
• Very strong - Strong covalent bonds
• Insoluble - there are no charged ions for polar molecules to interact with

Question 12

What are the properties of graphite?

(Include Mp/Bp, conductivity, strength and solubility)

Answer 12

• High melting and boiling points due to strong covalent bonds which require lots of energy to break
• Highly conductive - delocalised electrons are able to move freely through the layers and carry voltage
• brittle - there are weak intermolecular forces between the layers
• Insoluble - no charged ions for polar molecules to interact with

Question 13

What are the properties of Graphene?

(Include Mp/Bp, conductivity, strength and solubility)

Answer 13

• High melting and boiling points due to strong covalent bonds which require lots of energy to break
• Conductive - delocalised electrons move freely and carry voltage
• very strong - strong covalent bonds, 3 per carbon
• Insoluble - no charged ions for polar molecules to interact with

Question 14

What are the properties of ice?

(Include Mp/Bp, conductivity and density)

Answer 14

• low melting and boiling point due to wear intermolecular forces and hydrogen bonds
• unconductive - ions are present but not mobile
• less dense than water as arranged in a rigid tetrahedral structure that cages space.

Question 15

What factors affect Electronegativity?

Answer 15

• Nuclear Charge
• Atomic Radius
• Shielding

Question 16

What is the electronegativity trend down a group and why?

Answer 16

Electronegativity decreases. The atomic radius increases, and although the nuclear charge increases, so does the shielding.

Question 17

what is the electronegativity trend across a period and why?

Answer 17

Electronegativity increases. The nuclear charge increases, and the atomic radius decreases, whilst the shielding remains the same.

Question 18

What is a polar bond?

Answer 18

When electronegativies are different and unsymetrical, so the electrons in a covalent bond are attracted towards one end more than another. This causes one end to be slightly negative and one end to be slightly positive - these are called dipoles.

Question 19

What are the 3 main intermolecular forces in order from weakest to strongest?

Answer 19

1. Van Der Waals
2. Permanent Dipole-Dipole Attraction
3. Hydrogen Bonding

Question 20

What are Van der Waal Forces

Answer 20

Present in all molecular substances. Electrons are constantly moving, causing uneven electron distrubution and forming temporary dipoles. This induces temporary dipoles with neighbouring molecules, forming temporary induced dipole-dipole attraction.
The bigger the molecule the greater the van der waals forces.

Question 21

What are permanent dipole-dipole attractions

Answer 21

There are permanent dipole-dipole attractions between oppositely charged dipoles on polar molecules.

Question 22

What is Hydrogen bonding?

Answer 22

A positive H dipole is bonded to a lone pair of electrons on a very electronegative atom (F, O or N), forming strong intermolecular forces.

Question 23

Draw water hydrogen bonding

Answer 23

• hydrogen bond should be a dotted line between oppositely charged dipoles.
• refer to notes to check