Period 3 element

A period 3 element is an element found on the third 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 shells. 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 orbital, and six electrons join the 3p orbitals.

Periodic tables
Layouts	Standard Large table Inline f-block Vertical Text only Metals and nonmetals Blocks Valences Extension beyond the 7th period Large wide table Electron configurations Electronegativities Alternatives Janet table Crystal structure Discovery periods
List of elements by	Name etymology (symbol) Discovery Abundance (in humans) Nuclear stability Atomic properties Production
Data pages	Electron configurations Densities Electron affinities Melting points Boiling points Critical points Heats of fusion Heats of vaporization Heat capacities Vapor pressures Pauling electronegativities Ionization energies Atomic radii Electrical resistivities Thermal conductivities Thermal expansion coefficients Speeds of sound Elastic properties Hardnesses Abundances Oxidation states
Groups	1 (Alkali metals) 2 (Alkaline earth metals) 3 4 5 6 7 8 9 10 11 12 13 (Boron group) 14 (Carbon group) 15 (Pnictogens) 16 (Chalcogens) 17 (Halogens) 18 (Noble gases)
Other element categories	Periods Metals Transition metals Metalloids Nonmetals Lanthanides Actinides Superactinides Rare earth elements Platinum group metals (PGMs) Post-transition metals Refractory metals
Blocks	s-block p-block d-block f-block g-block
Periods	1 2 3 4 5 6 7 8 9 10
Category:Periodic table