It seems to me that the addition of electrons as you move across a period would cause an atom to become larger. However, I'm told it gets smaller. Why is this?

MathJax, which is already used by many SE sites supports the mhchem extension meant for typesetting chemical formulas like H2O or [AgCl2]- using simple syntax like \ce{H2O} or \ce{[AgCl2]-}. We'll likely be using chemical formulas very often, so a simple way to enter them would be very useful. A...

I ask we get LaTeX code enabled for our community. I am a computational chemist who regularly deals with mathematical equations. Being able to communicate these equations in a professional way such as LaTeX is rather necessary. Also, LaTeX is good for (with proper modules) chemical equations, ...

My understanding is that NaCl is an ionic compound, in which Cl becomes (effectively) Cl$^-$ and Na becomes Na$^+$. So I understand why I would get a "sea" of particles that would stick together. But why does the above mean that it will have a face centered cubic structure with the ions held in ...

The current reputation requirement for editing posts or approving suggested edits are 500 reputation during private beta 1000 reputation during public beta Those are very steep hurdles during the very early stages of beta for a new site. On the new Biology site we had something like 2-3 user...

I remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain enough carbon to support this theory, and is a tree's surface area actually large enough to obtain ...