A:镁的相对原子质量为12
B:镁原子在化学反应中易失2个电子
C:硫离子核内有16个质子
D:Mg2+与S2﹣的最外层电子数相等
看图回答问题
-- What present do you want to buy for your father?
-- _____ . They can keep his hands warm in winter.