Match the non-metallic elements with their correct symbols.

Non-metallic elements - a) Carbon b) Chlorine c) Oxygen d) Phosphorous e) Hydrogen f) Nitrogen g) Iodine h) Bromine i) Fluorine j) Silicon k) Sulphur

Symbols - $1. \mathrm{O} 2. \mathrm{I} 3. \mathrm{Si} 4. \mathrm{C} 5.\mathrm{Cl} 6. \mathrm{P} 7.\mathrm{F} 8. \mathrm{H} 9. \mathrm{S} 10. \mathrm{Br} 11. \mathrm{N}$

Match the noble gases with their correct symbols.

Noble gases - a) Helium b) Neon c) Argon d) Krypton e) Xenon f) Radon

Symbols - $1. \mathrm{Ar} 2. \mathrm{Xe} 3. \mathrm{Rn} 4. \mathrm{He} 5. \mathrm{Kr} 6. \mathrm{Ne}$

Explain the term compounds. Give the example of a compound containing

a) hydrogen and oxygen

b) carbon and oxygen

c) nitrogen and oxygen

d) calcium and oxgen