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.

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v t e 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
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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)
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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