把下列各符号表示的意义填写在空格内:
⑴ H________________________ ⑵ 2H_____________________
⑶ H2_______________________ ⑷ 2H2_____________________
把下列各符号表示的意义填写在空格内:
⑴ H________________________ ⑵ 2H_____________________
⑶ H2_______________________ ⑷ 2H2_____________________