(2) positive ion with a radius larger than the radius of this atom
Explanation;
-Atomic radius of an element is the measure of the size of its atom, while the ionic radius measures the size of an ion.
-When the atom loses its outermost electron it forms positively charged or cation. The ionic radius of the cation will be smaller than the atomic radius because the atom loses an electron energy shell.
Aluminium oxide has higher melting point than aluminium chloride because there nay be some impurities in the oxide which affects the intermolecular force of attraction