Video I took of the gas grill at my house catching on fire! 1  Comedy. 2  Standard YouTube License.
The sodium atom (atomic number 11), with 1 valence electron in its third energy level, would like to achieve the stability of its nearest noble gas neighbor, the neon (Ne) atom (atomic number 10), which contains 8 valence electrons in its second energy level.
Consider, for example, a sodium (Na) atom (atomic number 11), which is a metal atom (elements to the left of the heavy, stepped diagonal line in the periodic table are metals). The valence shell of the sodium atom is its third energy level, and it contains one electron.