Compute the difference in masses of one mole each of aluminium atoms and one mole of its ions? (Mass of electron is `9.1 xx 10^(-28)` g). Which of one is heavier?

Explanation

Ionisation of AI atoms occurs as `Al to Al^(3+) + 3e^(-)`
Therefore, `Al^(3+)` ion is formed AI atom by 3 electrons. Difference in mass of 1 mole of Al atoms and 1 mole of `Al^(3+)` ions.
=mass of `3 xx 6.022 xx 10^(23)` electrons.
`=(3 xx 6.022 xx 10^(23)) xx (9.1 xx 10^(-28))`g
(as mass of an electron `=9.1 xx 10^(-28)`g)
`=164.4 xx 10^(-5)g=1.644 xx 10^(-3)` g
1 mole of AI atoms is heavier than 1 mole of `Al^(3+)` ions.
It is because 1 mole of Al atoms have `e^(-) = 13 xx 6.022 xx 10^(23)` electrons and 1 mole of AI ion have `e^(-)=13 xx 6.022 xx 10^(23)` electrons and 1 mole of AI ion have `e^(-)=10 xx 6.022 xx 10^(23)` electrons.