how many elements are in 4c02?

Answer 1

4cO2??? I think you mean '4CO2.

This is carbon dioxide.

There are only two(2) elements in carbon dioxide, they are Carbon & Oxygen.

However, in one (1) molecule of carbon dioxide there are three(3) atoms, they are 1 carbon and 2 oxygen ; designated by the 'CO2'.

The prefix '4' indicates that there are 4 molecules of carbon dioxide. This means in 4CO2 there are 4 carbon toms and 8(4 x 2) oxygen atoms.

The CO2 the atoms are chemically combined. However, the '4' indicates that the four molecules are not chemically combined with each other, but discrete particles. (molecules).

NB . In atomic symbols a one letter symbol is always written as a capital letter 'C' (Carbon), not 'c'

If an atomic symbol contains two letters e.g. iron (Fe) , then the first letter is always a capital letter and the second letter is always a small case letter.