The total no. Of electron in 1 mole of CH4 can be calculated as under:
CH4 = 1(6) + 4(1) = 10 electrons.
1 molecule of methane has 10 electrons.
1 mole of methane has 6.023X1023 molecules of methane.
Number of electrons present in 1 molecule of methane = 10
Number of electrons present in 6.023X1023 molecules of methane = 6.023X1023 X 10 = 6.023X1024 electrons.