1.1 Chemical bonds, ionic, covalent and metallic

Question 1

Ionic bonding

Answer 1

• Metal combined with non-metal.
• Occurs in compounds formed from metals and non-metals.
• Particles are oppositely charged ions.

Question 2

Covalent bonding

Answer 2

• Non-metal combined with non-metal.
• Occurs in most non-metallic elements and compounds.
• Particles are atoms that share pairs of electrons.

Question 3

Metallic bonding

Answer 3

• Metals combined with metal.
• Occurs in metallic elements and alloys.
• Particles are atoms which share delocalised electrons

Question 4

Structure of metals

Answer 4

• Giant metallic lattice
• Regular rows of positive ions (that can slide on each other)
• Sea of delocalised electrons
• Strong electrostatic force of attraction.

Question 5

Properties of metals

Answer 5

• Conduct electricity (delocalised electrons are free to carry charge through the structure)
• Conduct thermal energy (delocalised electrons conduct thermal energy and are free to carry it through the structure)
• High MP (strong electrostatic force between positive ions and delocalised electrons require large sum of energy to overcome)
• Malleable (rows can slide over each other and bonds just reform).

Question 6

Structure of ionic compound

Answer 6

• Giant ionic lattice
• Constant ratio of positive to negative ions.
• Solid at room temperature

Question 7

Groups and allocated charges

Answer 7

• Group 1 = 1+
• Group 2 = 2+
• Group 3 = 3+
• Group 5 = 3-
• Group 6 = 2-
• Group 7 = 1-

Question 8

Limitations of using dot and cross diagram to represent giant lattice structure.

Answer 8

• Only shows few ions when there are thousands of ions.
• Not 3D reducing its complexity.

Question 9

Limitations of using ball and stick diagram to represent giant lattice structure.

Answer 9

• Physical bonds shown by sticks are misleading (bonds are not visible and are attracted by electrostatic forces).
• Size of atom not realistic

Question 10

Limitations of using two dimensional diagram to represent giant lattice structure.

Answer 10

• Not 3D so shows only one face of giant ionic lattice.

Question 11

Limitations of using three dimensional diagram to represent giant lattice structure.

Answer 11

• Only easily demonstrate substances that exist in 1:1 ratio like NaCl compared to Na²O.

Question 12

Structure of covalent bonded substances

Answer 12

• Can have small molecules that are covalently bonded
• Can have large molecules that are covalently bonded, like polymers.
• Can have giant covalent structure, like diamond or silicon dioxide.