Atomic structure enrichment question

Note the radii in nanometers would be 0.152nm ; 0.186nm and 0.231nm.

Electron arrangements

Li . Na K

Down the group there are shells

The outermost electron is from the nucleus.

(The increase in the nuclear charge is opposed by the repulsion from the electrons in the inner shells).

The electron is less strongly attracted to the nucleus .

The energy needed to remove the outer shell electron .