1. The sum of atomic masses of all the atoms in one formula unit of a substance is called:

2. Which one of the followings is the mixture of oxygen, nitrogen and carbon dioxide?

3. An atom or group of atoms having positive charge on it is called:

4. An atom or group of atoms having odd number of electrons is called:

5. A substance whose atoms have the same atomic number is called:

6. Anything that has mass and occupies space is called:

7. Which one of the followings has sharp and fixed melting point?

8. Which one of the followings shows the simplest whole number ratio of atoms in a substance?

9. One mole of any material contains chemical units equal to:

10. The sum of protons and neutrons in the nucleus of an atom is called: