Question

Explain why the atomic radius of fluorine is smaller than that of lithium​

Answer 1

1. Common knowledge : Go to the right of periodic table, the atomic radius is decreasing

2. Flurine has 9 protons and lithium has 3 protons. you know that the electron is attracted with the centre of the atom, that's why more proton, more 'energy' that attract to the centre and that's why it make the shape of the atom is smaller