Changes

==Organization==

==Organization==

Elements in the periodic table are ordered by number of [[proton]]s, and rows are arranged by number of [[electrons]]s in their outermost [[electron shell]].  Since farther out shells have more [[orbital]]s, this means that there will be more elements in the lower rows of the periodic table than in the higher rows.  For example, for [[principle quantum number] <i>n=1</i>, there is only one [[s-orbital]] available, which will fit only two electrons (due to the [[Pauli exclusion principle]], which states that no two electrons can have the same quantum numbers).  Therefore, only two elements can be in the top row of the periodic table.  As the [[principle quantum number]] increases, the number of electrons per shell rises, so the farther-down rows hold more elements.

Elements in the periodic table are ordered by number of [[proton]]s, and rows are arranged by number of [[electrons]] in their outermost [[electron shell]].  Since farther out shells have more [[orbital]]s, this means that there will be more elements in the lower rows of the periodic table than in the higher rows.  For example, for [[principle quantum number] <i>n=1</i>, there is only one [[s-orbital]] available, which will fit only two electrons (due to the [[Pauli exclusion principle]], which states that no two electrons can have the same quantum numbers).  Therefore, only two elements can be in the top row of the periodic table.  As the [[principle quantum number]] increases, the number of electrons per shell rises, so the farther-down rows hold more elements.

The [[group number]] tells how many electrons an element has in its outermost electron shell.  For example, every element in group 8A, the [[Nobel gases]], has its outermost electron shell completely full.

The [[group number]] tells how many electrons an element has in its outermost electron shell.  For example, every element in group 8A, the [[Nobel gases]], has its outermost electron shell completely full.