The Atmosphere (Chemistry)

[匿名]

2011-07-23 6:07 pm

1. Noble gas exists in air because it's very stable (won't form oxides easily)??
2. Why the most abundant noble gas is not helium?
Helium is an atom with the smallest size among noble gases. Its molecule is much harder to be separated. Why it's not the most abundant?
( or 它們的數量本身是既定了?)
3. The amount of argon is more than / less than CO2?
4. The amount of noble gases (decreasing order):
Argon, helium, neon, krypton, xenon?

Thanks for answering :)

回答 (1)

己式庚辛

2011-07-26 11:56 am

✔ 最佳答案

1.
you can say so.
they don't form many compounds, and are not fixed (in the ground, organisms etc.) easily. so they exist in elemental form.
in addition to that, they're unimolecular, leading to very weak van der Waal's force. they're all gas at room temp.

2.
separate from what? they exist as free individual atoms.
small doesn't mean abundant.

well, amount of elements in the universe is quite constant. when Earth forms, there's helium o Earth. however, helium is too light for the Earth's gravity to grab ---- it escapes into the space.
though argon is much LESS abundant in universe than helium, it's heavy enough to be retained by Earth's gravity. Also, there's ready production of argon, via radioactive decay of some other radioisotope (potassium-40).

3.
more, much more.
argon is about 0.93%, while carbon dioxide is about 0.03% .

4.
no.
argon, neon, helium, krypton, xenon .

👍 0 👎 0