Hello there,

As there is the case of oxygen gas, means we have O2. Firstly we calculate the number of moles in 3.2 g of this gas.

no. of moles = given mass / molar mass

= 3.2/32 = 0.1moles

Now we calculate the total number of molecules in this amount of O2.

= 0.1 * 6.022 * 10^(23)

Now we know that, one molecule of O2 has 2 atoms of oxygen and 1 atom of oxygen contains 8 electrons. So total no of electrons in 2 atoms/1 molecule are 16.

For total no of electrons in 3.2 g O2 are =

6.022 * 10^(22)  * 16

Hope it helps.