# An atom contains electrons protons and neutron if the mass of each neutrons is halved and each electron is doubled then the electron is doubled then the atomic mass of 12Mg24

Dear Student,

In 12Mg24,

12 is the atomic number i.e. number of protons (NOT number of electrons).

24 is the mass number. It is 12+12 (12 of protons and 12 of neutrons).
Mass of proton $\approx$Mass of neutron
Mass of electrons is negligible. So, even doubling it does not affect the atomic mass significantly

So, if mass of neutron is halved, the mass of 12 neutrons =  6.
Then atomic mass will be 12 (proton mass) + 6 (neutron mass) = 18

Regards

• 5
What are you looking for?