Structure of Atom – Solutions

1)
i)Calculate the number of electrons which will together weigh one gram.
ii)Calculate the mass and charge of one mole of electrons.
Solution:
i) Mass of an electron = 9.1 x 10^-28 g
9.1 x 10^-28 g is the mass of 1 electron
1 g is the mass of 1/ 9.1 x 10^-28 electrons
=1.099 x 10²⁷ electrons
Hence, the number of electrons that will together weigh one gram is = 1.099 x 10²⁷ electrons.
ii) One mole of electrons = 6.022 x 10^-23 electrons
Mass of one electron= 9.1 x 10^-28 g
Mass of 1 mole of electrons = 6.022 x 10^-23 x 9.1 x 10^-28 g
= 5.48 x 10^-4 g
Charge of one electron = 1.6 x 10^-19 C