What do you understand by chemical formula of a compound? What is its significance?

Define the following terms with an example of each:
a. Element
b. Compound
c. Metal
d. Non-metal
e. Metalloid

Write the symbols for the following elements and classify them as solid, liquid and gas.
Aluminum, carbon, chlorine, mercury, hydrogen and helium

Classify the following as metals, non-metals and metalloids .
Sodium, Bismuth, Silver, Nitrogen, Silicon, carbon, chlorine, Iron, copper.

Classify the following as elements and compounds.
Water, Common salt, Sugar, Carbon dioxide, Iodine and Lithium