Topic 3 - 3.4 - Shapes/Properties of Covalent Molecules

Question 1

Name all 4 of the shapes for covalent molecules

Answer 1

1. Tetrahedral
2. Trigonal Pyramidal
3. Angular
4. Linear

Question 2

What are the rules for a TETRAHEDRAL shape?

tip - tetra means 4

Answer 2

If you have 1 atom bonded to 4 other atoms, the shape is tetrahedral e.g methane

Question 3

What are the rules for an ANGULAR shape?

Answer 3

If there is 1 atom bonded to 2 other atoms, the shape is angular.

Question 4

What are the rules for a LINEAR shape?

Answer 4

If 1 atom is bonded to 1 other atom, the shape is linear.

Question 5

What are the rules for a TRIGONAL PYRAMIDAL shape?

tip - “tri” means 3

Answer 5

If you have 1 atom bonded to 3 other atoms, the shape is trigonal pyramidal.

Question 6

List 4 properties of COVALENT MOLECULES

Answer 6

• They are made up of two non-metals only
• They are insoluble
• They have low melting and boiling points
• They cannot conduct electricity EXCEPT water molecules

Question 7

Why can water molecules conduct electricty but other molecules can’t?

Answer 7

Because they can dissociate, forming ions (ions can conduct electricity)

Question 8

Give two reasons as to why covalent molecules are insulators

Answer 8

• molecules are not charged particles
• non-metals aren’t good at conducting electricity