稀有气体氦的分子式是____。

A.Na2He中Na为+1 价，He 为-1价

B.Na2He中Na、He元素质量比为 2:1

C.Na2He中既含金属元素，又含非金属元素

D.稀有气体很稳定，不与任何物质发生反应

A.属稀有惰性气体，无色，无味，微溶于水，不燃烧，也不能助燃。It is a rare inert gas, colorless, tasteless, slightly soluble in water, and does not burn or aid combustion.###SXB###B.氦是除氢气以外密度最小的气体，其密度是氢气的1.98倍，与空气的相对密为l/7.2。Helium is the least dense gas except hydrogen, with a density of 1.98 times that of hydrogen and a relative density of l/7.2 of air.###SXB###C.是贵重的稀有气体，天然气中含量甚微，不超过1％(体积比)。天然气中如果氦含量超过0.1％(体积比)时，就有提氦的工业价值。It is a valuable and rare gas, found in very small am

氦、氖、氩等稀有气体的分子是由双原子组成的。()

A.氪

B.氙

C.氦

D.氖

A.氪

B.氙

C.氦

D.氖

A.氦

B.氩

C.氪

D.氡

A.氖和氩

B.氦和氩

C.氦和氖

D.氖