(1)钠
(2)Na>O>H
(3)
(4)2Na+2H 2O==4NaOH+H 2↑;2Na 2O 2+2H 2O=4NaOH+O 2↑;离子键和非极性键;作呼吸面具和潜水艇里氧气得来源
(5)2H 2O 2
2H 2O+O 2↑