валентность определяется номером группы в котором стоит элемент
Al - 3 0 кислород всегда 2-х валентен 2х3=6 6/2 = 3 это кислород
6/3 = 2 это Al
Al2O3
Бромиды -это соли бромистоводородной кислоты HBr ...кислотный остаток у этой кислоты всегда 1 (Br)1 Аргентум - серебро 1-валентен...значит- AgBr
Ca3P2
Сульфид( соль сернистой кислоты H2SO3 кислотный остаток всегда 2
с медью 2-х валентной ... СuSO3 валентности равны
Оксид ( это реакция с кислородом- окисление) N2O5
не знаю что писать но спс за Hit the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are notified that any dissemination distribution or copying of this email and any attachments is intended only for the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you are not the intended recipient you.
.