ATOMS AND MOLECULES

Gap-fill exercise

  
Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
1.The first scientific theory of the atom was proposed by
2. Anything that has mass and occupies space is called
3. The sum of the number of and of an atom is called its mass number.
4. The mass of an atom is measured in
5. A molecule is a combination of two or more held together by strong chemical forces of attraction, i.e. chemical bonds.
6. The molecule is made of similar kind of atoms, then it is called molecule.
7. The molecule that consist of atoms of different elements is called molecule.
8. The number of atoms present in the molecule is called its ‘’.
9. The water molecule contains two hydrogen atoms and one oxygen atom. So its atomicity is
10. The mass of the molecule of an element or compound is measured in the C-12 scale and hence called mass.