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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: dolimitless on September 04, 2009, 02:23:41 PM

Title: Why are metals more dense than non-metals?
Post by: dolimitless on September 04, 2009, 02:23:41 PM

Im guessing its something due to their metallic bonding?

Title: Re: Why are metals more dense than non-metals?
Post by: Fridushka on September 04, 2009, 04:33:35 PM

ummm well as i know metals are solid at room temperature that's why they would be denser then nonmetals

Title: Re: Why are metals more dense than non-metals?
Post by: renge ishyo on September 04, 2009, 04:40:49 PM

Yup, metals are held together by metallic bonding which essentially means that each atom in the metal "shares" electrons with all the other atoms around it. An atom cannot stray far from its neighbors in a pure metal because if it did so it wouldn't be able to benefit from or contribute to this sea of electrons. So the density of a metal is limited by how far one atom can stray form another without disrupting the electron sea.

In contrast, most nonmetal gases form discrete molecules where the bonds formed are covalent and localized between only a few atoms. It is easy for instance for a single molecule of O₂ to stray quite far away from another molecule of O₂ since the two molecules are not strongly attached to each other. This ability allows a sample of oxygen gas to have a lower density at normal temperatures than a metal; it can spread out to fill space much more easily.