Student Question

Why don't most of the gases in the earth's atmosphere Contribute to the greenhouse effect 

Expert Answers

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Nitrogen gas (N2) and oxygen gas (O2) are the most abundant gases within Earth’s atmosphere. Nitrogen gas and oxygen gas are not greenhouse gases because they are symmetrical.

According to Chapter 4 of Greenhouse Gases that is posted by the University of Chicago, “changing the electric field within a gas molecule is how greenhouse gases interact with IR light”. Therefore, in order to absorb infrared light energy from the sun, a compound or molecule “must be electrically lopsided”. However, neither oxygen (O2) or nitrogen (N2), the most abundant gases within Earth’s atmosphere, are lopsided. Both oxygen gas and nitrogen gas are symmetrical. Therefore, the electrons are shared evenly between the bonds that hold the atoms together. There is little polarity within either molecule. Thus, there is little to no difference in the electrical field on either side of the molecules. As a result, the abundant nitrogen and oxygen molecules within Earth’s atmosphere, are not greenhouse gases.

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