Period 4 element

A period 4 element is an element in the fourth period (row) of the periodic table. It begins at potassium and ends at krypton. Period 4 has 18 elements.

Period 4 elements have electrons in the first four electron shells. All period 4 elements have one or more electrons in the fourth electron shell (valence electrons). When atomic number increases by one, another electron is added. Two electrons join the 4s orbital, ten electrons join the 3d orbital, and six electrons join the 4p 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