(1)用数字和符号表示: ①2个氢离子____; ②2个硫离子____; ③3个铵根离子______; ④2个氮分子_______; ⑤+5价氯元素_____; ⑥3个水分子____。 (2)请写出下列各符号的意义: ①2H______________________ ②3N2______________ ③_______________ ④4Na+______________________ ⑤2H2O____________________ ⑥3Fe2+________________________ |