Electronic configurations of various atoms relate to how electrons are filled in these atomic orbitals. Electronic configurations of atoms followed various rules to fill up their orbitals in sequences. The subshells are filled up by the electrons one after another if necessary for increasing their atomic numbers. Electronic configurations give a clear idea about the number of electrons in each subshell.
Electronic Configurations Definition
Electronic configurations mean the particular distribution of electrons in orbital shells one after another by a notation that lists the subshell symbols. The number of electrons in that subshell is put in the right position. The arrangement of electrons around the nucleus of a particular atom or molecule can be shown by following some rules in the electronic configurations issue.
We know, an atom consists of protons, neutrons, and electrons. The same number of protons and electrons are found in a neutral atom which is called atomic number. The electronic configurations help to identify the number and position of the atom in the periodic table.
History of electronic configurations
The electronic configurations issue was first used in at least the 1920s after discovering the principle of Niels Bohr’s atomic structure. He proposed that electrons are distributed in various orbits around a nucleus. This model was used by later scientists to describe the atomic structure. Arnold Sommerfeld developed the rules for the movements and locations of electrons in any atom.
Importance of electronic configurations
We know the various properties of atoms by the electronic configurations of atoms.
It is possible to identify the cationic and anionic issues from the electronic configurations of atoms.
The radical properties can be investigated from the electronic configurations of atoms.
The configuration of electrons is very important to know the bonding of electrons in any molecule.
The periodic properties of an atom can be known from the c electronic configurations of atoms.
The redox chemical reactions are also dependent on the electronic configurations of atoms.
Rules for Electronic Configurations of Atoms
The electronic configurations of atoms follow some rules which are given below:
Aufbau Principle: The word ‘Aufbau’ is a German word that means ‘Building up’. This principle states that electrons in various orbitals within atoms are filled one by one by following the increasing order of orbital energy. The energy of any atomic orbital is calculated by using the “n+l” rule. Here, the principal quantum number is denoted by n and the Azimuthal quantum number is denoted by l. This rule gives the idea that orbitals contain higher energy if it has a higher number of the n+l value.
The sequence of increasing order of energy of various orbital is given below:
1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,5f,6d,7p……………………
This big sequence can be remembered easily by following the method to write the increasing order of the orbitals. It is started from the top positions and the direction of the arrows gives the idea about the order of filling the orbitals of different atoms.
An example of the Aufabau Principle is given below:
The electronic configurations of Argon atom is 1s2 2s2 2p6 3s2 3p6
Pauli Exclusion Principle
This principle states that an orbital of atoms can only hold a maximum number of two electrons having the opposite spin direction. It is not possible for the existence of two electrons in the same atom to have identical values for all four quantum numbers in an orbital. Two electrons in any atom may have the same Principle, Azimuthal, and Magnetic numbers. But there are opposite spin electrons.
An example of the Pauli Exclusion Principle is given below:
The helium atom contains 2 bound electrons which occupy the outermost shell with opposite spins. For these two electrons, the principal quantum number (n) is 0, azimuthal quantum number (l)=0, and magnetic quantum number (ms)=0. The spin quantum number for two electrons contains +1/2 and -1/2 which are different values.
Hund’s Rule
This rule states that electrons are filled in all subshell orbitals in such a way that any orbital in a definite subshell is filled by an electron before a second electron enters the subshell.
An example of the Hund’s rule Principle is given below:
The electronic configuration of the nitrogen atom (Z=7) is 1s2 2s2 2p3.
For this atom, the 1s and 2s orbitals are filled in which 1s and 2s orbitals are pairs and antiparallel states respectively. Then 2p orbital remains in a filled state and is separated from each other and contains the same spin.
Electronic Configurations Examples
The electronic configurations of periodic atoms are given below:
The electron configuration of the Hydrogen atom (Z=1) is 1s1
The electron configuration of the Helium atom (Z=2) is 1s2
The electron configuration of the Lithium atom (Z=3) is [He]2s1
The electron configuration of the Beryllium atom (Z=4) is [He]2s2
The electron configuration of the Boron atom (Z=5) is [He]2s22p1
The electron configuration of the Carbon atom (Z=6) is [He]2s22p2
The electron configuration of the Nitrogen atom (Z=7) is [He]2s22p3
The electron configuration of the Oxygen atom (Z=8) is [He]2s22p4
The electron configuration of the Fluorine atom (Z=9) is [He]2s22p5
The electron configuration of the Neon atom (Z=10) is [He]2s22p6
The electron configuration of the Sodium atom (Z=11) is [Ne]3s1
The electron configuration of the Magnesium atom (Z=12) is [Ne]3s2
The electron configuration of the Aluminium atom (Z=13) is [Ne]3s23p1
The electron configuration of the Silicone atom (Z=14) is [Ne]3s23p2
The electron configuration of the Phosphorus atom (Z=15) is [Ne]3s23p3
The electron configuration of the Sulphur atom (Z=16) is [Ne]3s23p4
The electron configuration of the Chlorine atom (Z=17) is [Ne]3s23p5
The electron configuration of the Argon atom (Z=18) is [Ne]3s23p6
The electron configuration of the Potassium atom (Z=19) is [Ar] 3s1
The electron configuration of the Calcium atom (Z=20) is [Ar] 3s2
The electron configuration of Scandium atom (Z=21) is [Ar] 3d1 4s2
The electron configuration of Titanium atom (Z=22) is [Ar] 3d2 4s2
The electron configuration of Vanadium atom (Z=23) is [Ar] 3d3 4s2
The electron configuration of Chromium atom (Z=24) is [Ar] 3d5 4s1
The electron configuration of Manganese atom (Z=25) is [Ar] 3d5 4s2
The electron configuration of Iron atom (Z=26) is [Ar] 3d6 4s2
The electron configuration of Cobalt atom (Z=27) is [Ar] 3d7 4s2
The electron configuration of Nickel atom (Z=28) is [Ar] 3d8 4s2
The electron configuration of Copper atom (Z=29) is [Ar] 3d10 4s1
The electron configuration of Zinc atom (Z=30) is [Ar] 3d10 4s2
The electron configuration of Gallium atom (Z=31) is [Ar] 3d10 4s2 4p1
The electron configuration of Germanium atom (Z=32) is [Ar] 3d10 4s2 4p2
The electron configuration of Selenium atom (Z=34) is [Ar] 3d10 4s2 4p4
The electron configuration of Bromine atom (Z=35) is [Ar] 3d10 4s2 4p5
The electron configuration of Krypton atom (Z=36) is [Ar] 3d10 4s2 4p6
The electron configuration of the Rubidium atom (Z=37) is [Kr] 5s1
The electron configuration of the Strontium atom (Z=38) is [Kr] 5s2
The electron configuration of Yttrium atom (Z=39) is [Kr] 4d1 5s2
The electron configuration of Zirconium atom (Z=40) is [Kr] 4d2 5s2
The electron configuration of Niobium atom (Z=41) is [Kr] 4d4 5s1
The electron configuration of Molybdenum atom (Z=42) is [Kr] 4d5 5s1
The electron configuration of Technetium atom (Z=43) is [Kr] 4d5 5s2
The electron configuration of Ruthenium atom (Z=44) is [Kr] 4d7 5s1
The electron configuration of Rhodium atom (Z=45) is [Kr] 4d8 5s1
The electron configuration of the Palladium atom (Z=46) is [Kr] 4d10
The electron configuration of Silver atom (Z=47) is [Kr] 4d10 5s1
The electron configuration of Indium atom (Z=49) is [Kr] 4d10 5s2 5p1
The electron configuration of Tin atom (Z=50) is [Kr] 4d10 5s2 5p2
The electron configuration of Antimony atom (Z=51) is [Kr] 4d10 5s2 5p3
The electron configuration of Tellurium atom (Z=52) is [Kr] 4d10 5s2 5p4
The electron configuration of Iodine atom (Z=53) is [Kr] 4d10 5s2 5p5
The electron configuration of Xenon atom (Z=54) is [Kr] 4d10 5s2 5p6
The electron configuration of the Cesium atom (Z=55) is [Xe] 6s1
The electron configuration of the Barium atom (Z=56) is [Xe] 6s2
The electron configuration of Lanthanum atom (Z=57) is [Xe] 5d1 6s2
The electron configuration of Cerium atom (Z=58) is [Xe] 4f1 5d1 6s1
The electron configuration of Praseodymium atom (Z=59) is [Xe] 4f3 6s2
The electron configuration of Neodymium atom (Z=60) is [Xe] 4f4 6s2
The electron configuration of Promethium atom (Z=61) is [Xe] 4f5 6s2
The electron configuration of Samarium atom (Z=62) is [Xe] 4f6 6s2
The electron configuration of Europium atom (Z=63) is [Xe] 4f7 6s2
The electron configuration of Gadolinium atom (Z=64) is [Xe] 4f7 5d1 6s2
The electron configuration of Terbium atom (Z=65) is [Xe] 4f9 6s2
The electron configuration of Dysprosium atom (Z=66) is [Xe] 4f10 6s2
The electron configuration of Holmium atom (Z=67) is [Xe] 4f11 6s2
The electron configuration of Erbium atom (Z=68) is [Xe] 4f12 6s2
The electron configuration of Thulium atom (Z=69) is [Xe] 4f13 6s2
The electron configuration of Ytterbium atom (Z=70) is [Xe] 4f14 6s2
The electron configuration of Lutetium atom (Z=71) is [Xe] 4f14 5d1 6s2
The electron configuration of Hafnium atom (Z=72) is [Xe] 4f14 5d2 6s2
The electron configuration of Tantalum atom (Z=73) is [Xe] 4f14 5d3 6s2
The electron configuration of Tungsten atom (Z=74) is [Xe] 4f14 5d4 6s2
The electron configuration of Rhenium atom (Z=75) is [Xe] 4f14 5d5 6s2
The electron configuration of Osmium atom (Z=76) is [Xe] 4f14 5d6 6s2
The electron configuration of Iridium atom (Z=77) is [Xe] 4f14 5d7 6s2
The electron configuration of Platinum atom (Z=78) is [Xe] 4f14 5d8 6s2
The electron configuration of Gold atom (Z=79) is [Xe] 4f14 5d9 6s2
The electron configuration of Mercury atom (Z=80) is [Xe] 4f14 5d10 6s2
The electron configuration of Thallium atom (Z=81) is [Xe] 4f14 5d10 6s2 6p1
The electron configuration of Lead atom (Z=82) is [Xe] 4f14 5d10 6s2 6p2
The electron configuration of Bismuth atom (Z=83) is [Xe] 4f14 5d10 6s26p3
The electron configuration of Polonium atom (Z=84) is [Xe] 4f14 5d10 6s26p4
The electron configuration of Astatine atom (Z=85) is [Xe] 4f14 5d10 6s26p5
The electron configuration of Radon atom (Z=86) is [Xe] 4f14 5d10 6s26p6
The electron configuration of the Francium atom (Z=87) is [Rn] 7s1
The electron configuration of the Radium atom (Z=88) is [Rn] 7s2
The electron configuration of Actinium atom (Z=89) is [Rn] 6d1 7s2
The electron configuration of Thorium atom (Z=90) is [Rn] 6d2 7s2
The electron configuration of Protactinium atom (Z=91) is [Rn] 5f2 6d1 7s2
The electron configuration of Uranium atom (Z=92) is [Rn] 5f3 6d1 7s2
The electron configuration of Neptunium atom (Z=93) is [Rn] 5f4 6d2 7s2
The electron configuration of Plutonium atom (Z=94) is [Rn] 5f6 7s2
The electron configuration of Americium atom (Z=95) is [Rn] 5f7 7s2
The electron configuration of Curium atom (Z=96) is [Rn] 5f7 6d1 7s2
The electron configuration of Berkelium atom (Z=97) is [Rn] 5f9 7s2
The electron configuration of Californium atom (Z=98) is [Rn] 5f10 7s2
The electron configuration of Einsteinium atom (Z=99) is [Rn] 5f11 7s2
The electron configuration of Fermium atom (Z=100) is [Rn] 5f12 7s2
The electron configuration of Mendelevium atom (Z=101) is [Rn] 5f13 7s2
The electron configuration of Nobelium atom (Z=102) is [Rn] 5f14 7s2
The electron configuration of Lawrencium atom (Z=103) is [Rn] 5f14 7s2 7p1
The electron configuration of Rutherfordium atom (Z=104) is [Rn] 5f14 7s2 7p2
The electron configuration of Dubnium atom (Z=105) is [Rn] 5f14 6d3 7s2
The electron configuration of Seaborgium atom (Z=106) is [Rn] 5f14 6d4 7s2
The electron configuration of Bohrium atom (Z=107) is [Rn] 5f14 6d5 7s2
The electron configuration of Hassium atom (Z=108) is [Rn] 5f14 6d6 7s2
The electron configuration of Meitnerium atom (Z=109) is [Rn] 5f14 6d7 7s2
The electron configuration of Darmstadtium atom (Z=110) is [Rn] 5f14 6d9 7s1
The electron configuration of Roentgenium atom (Z=111) is [Rn] 5f14 6d10 7s1
The electron configuration of Copernium atom (Z=112) is [Rn] 5f14 6d10 7s2
The electron configuration of Nihonium atom (Z=113) is [Rn] 5f14 6d10 7s2 7p1
The electron configuration of Flerovium atom (Z=114) is [Rn] 5f14 6d10 7s2 7p2
The electron configuration of Moscovium atom (Z=115) is [Rn] 5f14 6d10 7s2 7p3
The electron configuration of Livermorium atom (Z=116) is [Rn] 5f14 6d10 7s2 7p4
The electron configuration of Tennessine atom (Z=117) is [Rn] 5f14 6d10 7s2 7p5
The electron configuration of Oganesson atom (Z=118) is [Rn] 5f14 6d10 7s2 7p6
Frequently Asked Questions (FAQs)
What are the electronic configurations of an atom?
Electronic configurations are the specific arrangement of electrons distributed among the orbital shells and subshells. Electronic configurations are used to express the orbitals of an atom in its ground state. The electronic configuration of any atom is essential to represent the cationic and anionic state of atoms during the loss of or gain of electrons in their orbital shells and subshells.
What are the rules for electronic configurations of atoms?
There must be followed the three rules for the electronic configurations of elements to fill up the electrons in orbitals. These rules are the Aufbau principle, Pauli’s exclusion principle, and Hund’s rules.
The Aufbau principle relates that the electrons in atomic orbital fill up in the increasing order of orbital energy level.
Pauli’s exclusion principle relates that it is not possible to have equal values of all four quantum numbers for two electrons in an atom.
Hund’s rule states that all the subshells in an orbital must be singly occupied before any subshell is doubly filled up.
What are the electronic configurations of copper atoms?
The electronic configuration of the copper atom is 1s2 2s2 2p6 3s2 3p6 3d104s1. This configuration can not follow the Aufbau Principle due to the existence of an energy gap between the 3d and the 4s orbitals.
