Home Science Atom Electron Configuration

Electron Configuration

Electronic configuration of elements in periodic table

Electronic configuration or general electron configuration or electronic structure of atoms or ions is the arrangement of orbital energy levels for s, p, d, and f-block elements of the periodic table. In chemistry or chemical science, electron holds the key to the chemical world for learning properties and position of elements in the periodic table. The electronic configuration or electron arrangement formula of the periodic table elements is used for better understanding the chemical properties.

Electronic configuration of elements of periodic table and general electron configuration rule for s, p, d and f-block elements

Oxidizing reducing properties, oxidation number, ionization energy, electron affinity, shielding effect, the polarity of chemical bonds, acids bases properties can be explained by the electronic configuration.

A reaction to reach chemical equilibrium is the change of electron configuration of reactant and product atoms. Hence the organic and inorganic chemical reactions are better understood by the electronic configuration of elements.

How to find electronic configuration?

To find the electron configuration formula first we find the order of electronic energy levels of s, p, d, and f orbitals or sub-levels. For example, 3s orbital has lower energy than 3p orbitals which again lower energy than the 3d level.

The modern periodic table classification like s, p, d, and f block elements is based on properties and general electron or electronic configuration of elements.

What are electron energy levels?

Energy levels are fixed distances where electrons are rotating around the nucleus with definite energy. The energy associated with a certain energy level increases with the increase of its distance from the nucleus.

The hydrogen atom contains only one electron in 1s hydrogen energy levels with electronic configuration 1s1.

But difficult for readers to remember the electron energy levels diagram for many electronic configurations. Therefore, the trivial way but most convenient way to remember these electronic energy levels is given below the diagram.

Electron or electronic configuration of elements in periodic table, group wise general formula for s, p-block and 3d series

  • The different electron orbitals originating from the same electronic energy levels are written in horizontal lines.
  • Now inclined parallel lines are drawn through the electronic orbitals according to the above picture.
  • Filling up the different orbitals by the number of electrons will follow these lines configuration. According to above diagram structure, configuration energy levels with electron constructed the following ordering, 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s < 5f…

Number of electrons in energy levels

The filling up electronic orbitals with electrons around the nucleus of atoms takes place according to certain rules. The maximum number of electrons in the main energy levels = 2n2, where n = principal quantum number.

The maximum number of the electron in sub-shell like s, p, d, and f orbitals = 2(2l + 1). Where l = 0, 1, 2, 3 for s, p, d, f orbitals. Therefore, s, p, d, f energy levels have a maximum of 2, 6, 10, 14 electrons respectively.

Number of electrons in orbitals energy levels to find group wise electronic configuration of all periodic table elements

Aufbau principle and electron configuration

German scientist Aufbau expresses the building up principle for the electron configuration process in different electronic orbitals of atoms. According to this principle, the electrons are filled up in order of energy.

The orbitals with the lowest energy filled up first while the highest energy orbital filled up in the end. The electron will tend to form maximum spin. Electrons with similar spin are configured first.

What is Hund’s rule?

According to Hund’s rule, electrons are filling in the orbital with maximum spin multiplicity. Spin pairing occurs only when vacant orbitals of similar energy are not available for occupation.

Electronic configuration and periodic table

The electronic configuration formula uses to derive some basic properties like the electromagnetic spectrum, chemical bonding, electric polarization, dipole moment, hydrogen bonding, etc. Modern periodic tables are classified on the basis of chemical behavior and the electronic configuration of elements.

The electron configuration formula of elements must be connected with the periodic table. According to electronic configuration, the periodic table elements are classified into four blocks s, p, d, and f-block elements.

Electronic configuration of s block elements

For s-block elements, the electron enters the ns-orbitals and is progressively filled with atomic number.

Group-1 and 2 belong to s-block elements in the periodic table with general electron configuration ns1→2, where n = number of electronic shells or the number of periods in which the element is present.

Electronic configuration of group-1 elements

Group-1 or IA in the periodic table contains seven elements like hydrogen, lithium, sodium, potassium, rubidium, cesium, and francium.

The general electronic configuration of valence electron = ns1, where n = 1 to 7. Due to the presence of one electron in the outer electronic structure, they have very low ionization energy but very high electron affinity.

Atomic number Symbol Name Electronic configuration
1 H Hydrogen 1s1
3 Li Lithium 1s2 2s1
11 Na Sodium [Ne] 3s1
19 K Potassium [Ar] 4s1
37 Rb Rubidium [Kr] 5s1
55 Cs Cesium [Xe] 6s1
87 Fr Francium [Rn] 7s1

Electronic configuration of group-2 elements

The elements of Group-2 or IIA in the periodic table are beryllium, magnesium, calcium, strontium, barium, and radium. They are also called alkaline earth metals.

The valence shell electronic configuration of group-2 elements or alkaline earth metals is ns2, where n = 1 to 6.

Atomic Number Symbol Name Electronic configuration
4 Be Beryllium 1s2 2s2
12 Mg Magnesium [Ne] 3s2
20 Ca Calcium [Ar] 4s2
38 Sr Strontium [Kr] 5s2
56 Ba Barium [Xe] 6s2
88 Ra Radium [Rn] 7s2

Electronic configuration of p block elements

The elements in which the p-orbital are progressively filled by electrons are called p-block in the periodic table. Helium whose electronic configuration 1s2 but Helium is a member of p-block elements.

p-block contains six groups from group-13 to group-18. The general electronic configuration formula to find the outer electron configuration of the p-block element is ns2 np1→6.

Electronic configuration of group-13 elements

Group-13 or IIIA contains five elements, boron, aluminum, gallium, indium, and thallium. The valence shell electron configuration of group-13 elements is ns2 np1.

Atomic number Symbol Name Electronic configuration
5 B Boron 1s2 2s2 2p1
13 Al Aluminum [Ne] 3s2 3p1
31 Ga Galium [Ar] 3d10 4s2 4p1
49 In Indium [Kr] 4d10 5s2 5p1
81 Tl Thallium [Xe] 4f14 5d10 6s2 6p1
113 Nh Nihonium [Rn] 5f14 6d10 7s2 7p1

Electronic configuration of group-14 elements

Carbon, silicon, germanium, tin, and lead in the periodic table belong to group-14 or IVA. The general electronic configuration of group-14 elements is ns2 np2, where n = 2 to 6.

Atomic number Symbol Name Electronic configuration
6 C Carbon 1s2 2s2 2p2
14 Si Silicon [Ne] 3s2 3p2
32 Ge Germanium [Ar] 3d10 4s2 4p2
50 Sn Tin [Kr] 4d10 5s2 5p2
82 Pb Lead [Xe] 4f14 5d10 6s2 6p2
114 Fl Flerovium [Rn] 5f14 6d10 7s2 7p2

Electronic configuration of group-15 elements

The five elements of Group-15 or VA are nitrogen, phosphorus, arsenic, antimony, and bismuth. The electronic configuration of group-15 elements is ns2 np3, where n = 2 to 6.

Atomic number Symbol Name Electronic configuration
7 N Nitrogen 1s2 2s2 2p3
15 P Phosphorus [Ne] 3s2 3p3
33 As Arsenic [Ar] 3d10 4s2 4p3
51 Sb Antimony [Kr] 4d10 5s2 5p3
83 Bi Bismuth [Xe] 4f14 5d10 6s2 6p3
115 Mc Moscovium [Rn] 5f14 6d10 7s2 7p3

Electronic configuration of group-16 elements

Oxygen, sulfur, selenium, tellurium, and polonium in the periodic table belong to group-16 or VIA. The general electronic configuration of group-16 elements is ns2 np4, where n = 2 to 6.

Atomic number Symbol Name Electronic configuration
8 O Oxygen 1s2 2s2 2p4
16 S Sulfur [Ne] 3s2 3p4
34 Se Selenium [Ar] 3d10 4s2 4p4
52 Te Tellurium [Kr] 4d10 5s2 5p4
84 Po Polonium [Xe] 4f14 5d10 6s2 6p4
116 Lv Livermorium [Rn] 5f14 6d10 7s2 7p4

Electronic configuration of group-17 elements

Fluorine, chlorine, bromine, iodine, and astatine in the periodic table belong to group-17 or VIIA. The general electronic configuration of group-17 elements is ns2 np5, where n = 2 to 6.

Atomic number Symbol Name Electronic configuration
9 F Fluorine 1s2 2s2 2p5
17 Cl Chlorine [Ne] 3s2 3p5
35 Br Bromine [Ar] 3d10 4s2 4p5
53 I Iodine [Kr] 4d10 5s2 5p5
85 As Astatine [Xe] 4f14 5d10 6s2 6p5
117 Ts Tennessine [Rn] 5f14 6d10 7s2 7p5

Electronic configuration of noble gases

Neon, argon, krypton, xenon, and radon in the periodic table belong to group-18 or noble gases. The general electronic configuration of noble gases or group-18 elements is ns2 np6, where n = 1 to 6.

Atomic Number Symbol Name Electronic configuration
2 He Helium 1s2
10 Ne Neon [He] 2s2 2p6
18 Ar Argon [Ne] 3s2 3p6
36 Kr Krypton [Ar] 3d10 4s2 4p6
54 Xe Xenon [Kr] 4d10 5s2 5p6
86 Rn Radon [Xe] 4f14 5d10 6s2 6p6
118 Os Oganesson [Rn] 5f14 6d10 7s2 7p6

Electronic configuration of d block elements

The elements in which the electron enters in (n−1)d orbital are called d-block elements. These are placed in the middle of the periodic table, between s and p-block elements due to their chemical behavior like boing point, melting by specific heat, density, ionization energy, bonding, etc.

The general electronic configuration of valence electron of 3d, 4d, 5d, 6d elements represented as ns0,1,2 (n−1)d1→10.

These elements are called transition metals or elements. The names, symbols, and valence shell electronic configuration of all the d-block elements or transition metals are given below the picture,

General electron or electronic configuration of d-block elements or transition metals in periodic table

Electronic configuration of 3d-block Elements

The first crystalline solid metal in the 3d-series or first transition series starts with scandium and ends with zinc. When the twenty-first electron goes to the next available higher energy 3d orbital, the five 3d subshells fill with ten electrons.

The general electronic configuration of valence electron of 3d series or first transition series like scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc is [Ar] 4S1→2 3d1→10.

Atomic number Symbol Name Electronic configuration
21 Sc Scandium [Ar] 4s2 3d1
22 Ti Titanium [Ar] 4s2 3d2
23 V Vanadium [Ar] 4s2 3d3
24 Cr Chromium [Ar] 4s1 3d5
25 Mn Manganese [Ar] 4s2 3d5
26 Fe Iron [Ar] 4s2 3d6
27 Co Cobalt [Ar] 4s2 3d7
28 Ni Nickel [Ar] 4s2 3d8
29 Cu Copper [Ar] 4s1 3d10
30 Zn Zinc [Ar] 4s1 3d10

4d-block elements

Atomic number Symbol Name Electronic configuration
39 Y Yttrium [Kr] 4d1 5s2
40 Zr Zirconium [Kr] 4d2 5s2
41 Nb Niobium [Kr] 4d3 5s2
42 Mo Molybdenum [Kr] 4d5 5s1
43 Tc Technetium [Kr] 4d5 5s2
44 Ru Ruthenium [Kr] 4d7 5s1
45 Rh Rhodium [Kr] 4d8 5s1
46 Pd Palladium [Kr] 4d10 5s0
47 Ag Silver [Kr] 4d10 5s1
48 Cd Cadmium [Kr] 4d10 5s2

5d-block elements

Atomic number Symbol Name Electronic configuration
57 La Lanthanum [Xe] 5d1 6s2
72 Hf Hafnium [Xe] 4f14 5d2 6s2
73 Ta Tantalum [Xe] 4f14 5d3 6s2
74 W Tungsten [Xe] 4f14 5d4 6s2
75 Re Rhenium [Xe] 4f14 5d5 6s2
76 Os Osmium [Xe] 4f14 5d6 6s2
77 Ir Iridium [Xe] 4f14 5d7 6s2
78 Pt Platinum [Xe] 4f14 5d9 6s1
79 Au Gold [Xe] 4f14 5d10 6s1
80 Hg Mercury [Xe] 4f14 5d10 6s2

6d-block elements

Atomic number Symbol Name Electronic configuration
89 Ac Actinium [Rn] 6d1 7s2
104 Rf Rutherfordium [Rn] 5f14 6d2 7s2
105 Db Dubnium [Rn] 5f14 6d3 7s2
106 Sg Seaborgium [Rn] 5f14 6d4 7s2
107 Bh Bohrium [Rn] 5f14 6d5 7s2
108 Hs Hassium [Rn] 5f14 6d6 7s2
109 Mt Meitnerium [Rn] 5f14 6d7 7s2
110 Ds Darmstadtium [Rn] 5f14 6d9 7s1
111 Rg Roentgenium [Rn] 5f14 6d10 7s1
112 Cn Copernicium [Rn] 5f14 6d10 7s2

Exceptional electron configuration

Chromium, and copper, the 3d elements of our environment reveal their general form of electron or electronic configuration trends in the periodic table. The general electronic configuration valence electron of chromium and copper are [Ar]4s2 3d4 and [Ar] 4s2 3d9.

In the periodic table elements, the half-filled and filled orbitals electron configuration formula is relatively more stable than the partially filled orbitals. Thus 3d orbital of chromium and copper recording to form new electronic configuration like [Ar]4s1 3d5 and [Ar] 4s1 3d10 to gain extra chemical stability by exchange energy.

Electron configuration of f block elements

4f-block elements

Atomic number Symbol Name Electronic configuration
58 Ce Cerium [Xe] 4f15d16s2
59 Pr Praseodymium [Xe] 4f36s2
60 Nd Neodymium [Xe] 4f46s2
61 Pm Promethium [Xe] 4f56s2
62 Sm Samarium [Xe]4f66s2
63 Eu Europium [Xe] 4f76s2
64 Gd Gadolinium [Xe] 4f75d16s2
65 Tb Terbium [Xe] 4f96s2
66 Dy Dysprosium [Xe] 4f106s2
67 Ho Holmium [Xe] 4f116s2
68 Er Erbium [Xe] 4f126s2
69 Tm Thulium [Xe]4f136s2
70 Yb Ytterbium [Xe] 4f146s2
71 Lu Lutetium [Xe] 4f145d16s2

5f-block elements

Atomic number Symbol Name Electronic configuration
90 Th Thorium [Rn] 6d27s2
91 Pa Protactinium [Rn] 5f26d17s2
92 U Uranium [Rn] 5f36d17s2
93 Np Neptunium [Rn] 5f46d17s2
94 Pu Plutonium [Rn] 5f67s2
95 Am Americium [Rn] 5f77s2
96 Cm Curium [Rn] 5f76d17s2
97 Bk Berkelium [Rn] 5f97s2
98 Cf Californium [Rn] 5f107s2
99 Es Einsteinium [Rn] 5f117s2
100 Fm Fermium [Rn] 5f127s2
101 Md Mendelevium [Rn] 5f137s2
102 No Nobelium [Rn] 5f147s2
103 Lw Lawrencium [Rn] 5f147s27p1