bonding

Question 1

Explain the behaviour of ionic compounds with structure.

Answer 1

• Ionic compounds conduct electricity when molten or dissolved due to the ions being free to move and carry charge in these states, when usually they’d be fixed in position.
• Ionic compounds have high melting points due to strong electrostatic forces.
• Ionic compounds dissolve in water becasue water molecules are polar, so their charge can pull ions away from the lattice.

Question 2

Explain the behaviour of graphite with structure. (5)

Answer 2

• Graphite is slippery and can be used as a lubricant because the van der Waals forces between the flat sheets are easily broken so they can easily slide over each other.
• Graphite conducts electricity because it contains delocalised electrons.
• Graphite is lightweight because its layers are far apart compared with the length of its covalent bonds.
• Graphite has a high melting point due to strong covalent bonds.
• Graphite is insoluble because its covalent bonds are too strong to be broken by water.

Question 3

Explain the behaviour of diamond with structure. (5)

Answer 3

• Diamond has a very high melting point due to strong covalent bonds.
• It is very hard due to its tetrahedral shape: the bonds are equally strong in any direction.
• It is a good thermal conductor because vibrations travel easily through the lattice.
• It can’t conduct electricity because it has no delocalised electrons.
• It is not soluble, as its covalent bonds are too strong to break.

Question 4

What is dative covalent bonding?

Answer 4

Dative covalent bonding happens when both electrons in a bond come from one atom.

Question 5

What is the shape and bond angle of a molecule with 2 electron pairs and no lone pairs?

Answer 5

Linear and 180

Question 6

What is the shape and bond angle of a molecule with 3 electron pairs and no lone pairs?

Answer 6

Trigonal planar and 120

Question 7

What is the shape and bond angle of a molecule with 4 electron pairs and no lone pairs?

Answer 7

Tetrahedral and 109.5

Question 8

What is the shape and bond angle of a molecule with 4 electron pairs and 1 lone pair?

Answer 8

Trigonal pyramidal and 107

Question 9

What is the shape and bond angle of a molecule with 4 electron pairs and 2 lone pairs?

Answer 9

Bent and 104.5

Question 10

What is the shape and bond angle of a molecule with 5 electron pairs and no lone pairs?

Answer 10

Trigonal bipyramidal, 120 and 90

Question 11

What is the shape and bond angle of a molecule with 5 electron pairs and 1 lone pair?

Answer 11

Seesaw, 102 and 87.

Question 12

What is the shape and bond angle of a molecule with 5 electron pairs and 2 lone pairs?

Answer 12

T-shaped and 88.

Question 13

What is the shape and bond angle of a molecule with 6 electron pairs and no lone pairs?

Answer 13

Octahedral and 90

Question 14

What is the shape and bond angle of a molecule with 6 electron pairs and 2 lone pairs?

Answer 14

Square planar and 90.

Question 15

Define electronegativity.

Answer 15

Electronegativity is an atom’s ability to attract the electron pair in a covalent bond.

Question 16

What causes a permanent dipole?

Answer 16

Ina covalent bond between two atoms of different electronegativities, the bonding electrons will be pulled towards the more electronegative atom, making the bond polar, causing a permanent dipole.