What is bleach made out of?

This chart represents the melting point of several substance. what besy explains the high melting point of the salt?

Why does his teacher ask him to balance the equation by including the correct coefficient

If it is an isoelectronic series select true, if not select false. o2-, s2-, se2-, te2- na+, k+, rb+, cs+ n3-, p3-, as3-, sb3- ag, cd+, sn3+, sb4+ f-, cl-, br-, i- f-, ne, na+, mg2+ s2-, s, s6+