Please help me asap!!

Nonpoint source pollution is difficult to control because it

Athe top of a hill, an athlete on a skateboard has x joules of mechanical energy. how much mechanical energy will she have at the bottom of the hill? ignore the effects of friction.

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+