Atoms, elements and compounds

1

Which of these is the smallest particle?

2

Which of these is the correct symbol for magnesium?

3

Which statement about atoms and molecules is correct?

4

How many different atoms are there in a compound?

5

Approximately how many elements are there?

6

Which one is a compound?

7

Which of these contains two carbon atoms and six hydrogen atoms?

8

Which of these contains four hydrogen atoms?

9

How many atoms are there in total in a molecule of sulfur trioxide, SO3?

10

Why does air not have a definite formula?