|MadSci Network: Chemistry|
Hi Tonie, As a good rule of thumb, elements that tend to gain electrons are at the right of the periodic table of elements (before inert gases) and those that tend to give electrons are at the left of the periodic table. A good way to remember this is by looking at the situation of the element in the periodic table compared with the situation of the nearest inert gas element (helium, neon, argon, krypton, xenon, radon). All elements will try to "look like" its nearest inert gas element. For exemple, oxygen is nearest to neon (two spaces before neon) and it will tend to gain two electrons so that it "looks like" neon (i.e. have as much electrons as neon). Sodium which is one space forward of neon will tend to give one electron so that it will have the same amount of electrons as neon. Most of the time, this rule apply although there is some exceptions. The best way to know which one will tend to give or receive electrons is by looking at the element's orbitals although this is a little bit more complicated. I hope this answer helps you a little. Ciao! Mike.
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