Week 5 Homework
1. The elements that form covalent compounds are non-metals and metalloids.
2. The term covalent bond is a chemical bond that involves sharing a pair of electrons
between atoms in a molecule.
3. An electrons “dot and cross” diagram represents the outer shell of a particular element.
4. Covalent compounds have the common properties of
- They usually exist as gases, liquids or solids with low melting points because the forces
of attraction between the molecules are weak
- They generally do not conduct electricity because they are not made up of ions
- They are usually insoluble in water
5. The difference between single covalent bonds and triple covalent bonds can be easily
seen on a “dot and cross” diagram.
Single covalent bond:
Triple covalent bond:
6. A) Sulfur trioxide- Triple covalent bond
B) Chloroform- Quadruple covalent bond
C) Acetylene- Triple covalent bond
7. Dot and cross diagrams
A) Tetrachloromethane (CCL4):
B) Ammonia (NH3):
C) Carbon Disulfide (CS2):
8) The noble gases do not form covalent compounds because they have a full outer shell
and do not want to share because they are so strong with the full shell.
9) Both CO2 and O2 are both molecules because they are a full tight mixture that is
closely bound together.
10) Silicon dioxide, commonly known as silica or sand, is a hard solid covalent compound
with a very high melting point. Structure is: