What is an atom?

What are the 3 most abundant atoms on the earth?

How do hot air balloons float?

Why is hydrogen considered as an element?

Why is water considered as compound?

Explain the characteristics of compounds

Differentiate between elements and compounds

Comparative properties of metals and non-metals. Give three examples of each.

Write down the properties of metalloids

(i) Draw the symbol for some elements as proposed by Dalton.
(ii) What are rules to be followed while assigning symbol to element.