What is Period 3 element?
A '''period 3 element''' is an [[Chemical element|element]] found on the third [[period (periodic table)|period]] (row) of the [[periodic table]]. The row has eight elements [[sodium]], [[magnesium]], [[aluminium]], [[silicon]], [[phosphorus]], [[sulfur]], [[chlorine]], and [[argon]]. Period 3 elements have [[electrons]] in the first three [[electron shell]]s. The first and second electron shells are always full. The third electron shell ([[valence electrons]]) fills when atomic number gets bigger. Two electrons join the 3s [[atomic orbital|orbital]], and six electrons join the 3p orbitals. {{Periodic tables footer}} {{chem-stub}} [[Category:Periodic table]]