How many oxygen atoms are as large as one copper atom?

To solve this problem, you need to remember that the relative atomic mass of the elements is indicated in the periodic table of chemical elements. If we know the symbols of chemical elements, we can easily find it.
Oxygen is O, the serial number is 8, and the relative atomic mass (Ar) is 16.
Cuprum – Cu, serial number – 29, and relative atomic mass – 64.
To find out how many oxygen atoms have the same mass as a copper atom, you need: Ar (Cu) / Ar (O) = 64/32 = 2. This means that 2 O atoms weigh as much as one Cu atom.