Why does barium have a larger atomic radius than beryllium!

I think that it is related to the orbitals and the electron pairs in each atom.

try reading about "Vsepr" theory

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

passing a magnet thought the

mixture , because iron gets attracted to magnet .