Chemical elements of the fourth period

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The fourth period of the periodic table of the elements contains all chemical elements that have exactly four electron shells in the atom . The innermost (first) electron shell is fully occupied and has two electrons . The second electron shell is also fully occupied and has eight electrons. The third electron shell has a minimum of eight and a maximum of 18 electrons. The outermost (fourth) electron shell, also called the valence shell , can hold between one and eight electrons. Thus there are a total of 18 chemical elements in the fourth period.

Extract from the periodic table

group 1 2 3 4th 5 6th 7th 8th 9 10 11 12 13 14th 15th 16 17th 18th

I. II
III IV V VI VII VIII
Atomic number
symbol 		19
K 		20
approx 		21
Sc 		22
Ti 		23
V 		24
Cr 		25
mn 		26
feet 		27
Co 		28
Ni 		29
Cu 		30
notes 		31
Ga 		32
Ge 		33
As 		34
Se 		35
Br 		36
kr


Alkali metals Alkaline earth metals Transition metals other metals Semi-metals Halogens Noble gases

Magic number

The chemical elements calcium and nickel with atomic numbers 20 and 28, respectively, have a higher stability in the basic state of the atomic nucleus than neighboring nuclides . These special ordinal numbers are called magic numbers .

Number of electrons in the electron shells

Electron shell Number of electrons comment
All in all s orbital p orbital d orbital f orbital
1 2 2 - - - innermost electron shell
2 8th 2 6th - -
3 8 to 18 2 6th 0 to 10 -
4th 1 to 8 1 to 2 0 to 6 - - outermost electron shell , valence shell

list

Atomic number symbol Surname Element category Physical state Electron configuration
19th K potassium Alkali metals firmly [ Ar ] 4s 1
20th Approx Calcium Alkaline earth metals firmly [Ar] 4s 2
21st Sc Scandium Transition metals firmly [Ar] 3d 1 4s 2
22nd Ti titanium Transition metals firmly [Ar] 3d 2 4s 2
23 V Vanadium Transition metals firmly [Ar] 3d 3 4s 2
24 Cr chrome Transition metals firmly [Ar] 3d 5 4s 1
25th Mn manganese Transition metals firmly [Ar] 3d 5 4s 2
26th Fe iron Transition metals firmly [Ar] 3d 6 4s 2
27 Co Cobalt Transition metals firmly [Ar] 3d 7 4s 2
28 Ni nickel Transition metals firmly [Ar] 3d 8 4s 2
29 Cu copper Transition metals firmly [Ar] 3d 10 4s 1
30th Zn zinc Transition metals firmly [Ar] 3d 10 4s 2
31 Ga gallium other metals firmly [Ar] 3d 10 4s 2 4p 1
32 Ge Germanium Semi-metals firmly [Ar] 3d 10 4s 2 4p 2
33 As arsenic Semi-metals firmly [Ar] 3d 10 4s 2 4p 3
34 Se selenium Semi-metals firmly [Ar] 3d 10 4s 2 4p 4
35 Br bromine Halogens liquid [Ar] 3d 10 4s 2 4p 5
36 Kr krypton Noble gases gaseous [Ar] 3d 10 4s 2 4p 6