Electronic Configuration of First 30 Elements - Meaning, Definition, Elements, Functions, FAQs

Electronic configuration of elements is written in increasing order of energy of electrons present in different shells. The four types of quantum numbers provide various information related to electrons. Students are advised to follow Pauli's exclusion principle, Aufbau's rule, and Hund's rule while writing electronic configuration. The electronic configuration of the first 30 elements is given below, which can be used as a reference while writing the electronic configuration of various cations and anions formed by these elements.

What are electronic configurations?

An electronic configuration, also known as an electronic structure, is the arrangement of electrons at different energy levels surrounding an atomic nucleus. The electronic configuration of a molecule is the distribution of electrons in distinct molecular orbitals. The importance of the molecule cannot be overstated. It is possible to determine the number of electrons in bonding and antibonding molecular orbitals from a molecule's or molecular ion's electronic configuration.

• The electrical configuration of an element is used to figure out where electrons are located in that element.

• From the lowest to the highest energy level, electrons are arranged in ascending order.

• The electrical configuration of an element is largely determined by its atomic number.

• The electrical configuration of an atom is helpful in determining an element's valency, which aids in determining the element's reactivity.

• The atomic spectra can also be interpreted using the electrical configuration.

• Noble gases with totally filled outermost electrons, such as Neon, Argon, and Helium, are the most stable. Noble gases have filled valence shells, which give them their inertness.

• Copper and chromium have a peculiar electrical structure in which the 3d- orbitals are filled first, rather than the 4s orbitals.

• In chromium([Ar] 3d⁵ 4s¹) the d-orbital, which is filled with single electrons, boosts the atom's stability. Similarly, the d-orbital of Copper [Ar] 3d¹⁰ 4s¹ is totally filled with paired electrons, ensuring the atomic structure's stability.

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The four subshell labels are s, p, d, and f, and the electrical configuration of atoms is represented by a sequence of the label names of each atomic subshell, with the total amount of electrons assigned to that specific subshell expressed in superscript. In each of the subshells s, p, d, and f, the maximum number of electrons allowed is 2, 6, 10, and 14 accordingly. Noble gases, which have entirely filled outermost shells and can be prefixed to the outer shell of the element, can also be used to write the electronic configuration of elements, and the electronic configuration must be noted. The electron configuration of an element describes the distribution of electrons in its atomic orbitals. All electron-containing atomic subshells are placed in a sequence in atomic electron configurations, which follows a standard nomenclature (with the number of electrons they possess written in superscript). For example, sodium's electron configuration is 1s² 2s² 2p⁶ 3s¹.

On the other hand, standard notation frequently results in extended electron configurations (especially for elements having a relatively large atomic number). In some cases, a shortened or condensed notation may be used instead of the standard notation. In the abbreviated notation, the series of completely full subshells that correspond to a noble gas's electronic configuration are replaced by the noble gas's symbol in square brackets. As a result, the electron configuration of sodium is [Ne] 3s¹ (the electron configuration of neon is 1s² 2s² 2p⁶, which can be abbreviated to [He] 2s² 2p⁶).

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What are the three rules that must be observed while writing electronic configurations of elements?

• The Aufbau principle states that before occupying an orbital associated with a higher energy level, electrons must entirely fill the atomic orbitals of the previous energy level. In the sequence of increasing orbital energy level, electrons occupy orbitals.

• According to Pauli's exclusion principle, No two electrons may have the same values for all four quantum numbers. As a result, each subshell of an orbital may only hold a maximum of two electrons, both of which must have opposite spins.

• Hund's rule of maximum multiplicity states that all subshells in an orbital must be occupied singly before any subshell can be twice occupied. Furthermore, all electrons in singly occupied subshells must have the same spin (in order to maximise the overall spin).

The above table contains atomic number 1 to 30 elements with symbols and electronic configuration. The electronic configuration of elements can also be written in the form of electronic configuration of nearest noble gases.

For example- In this table, we can represent electronic configuration of elements from 21 to 30 in the form of Ar as Argon (atomic number - 18) is the nearest noble gas for first series elements of d-block.

From the above table, students can observe that atomic number 20 to 30 elements electronic configuration has no electrons in d orbitals as d orbital is absent for K and L shells. While electronic configuration of elements from 21 to 30 has presence of M shell and therefore the electrons in d orbital are also observed.

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How to write electronic configuration of elements

We have to follow the above mentioned three rules while writing electronic configurations. To get different quantum numbers, we first have to extract various information, such as the number of electrons, possible number of various shells and orbitals, energy levels, etc. of elements by using the periodic table. Refer to the example of electronic configuration of iron mentioned below in order to get a better understanding.

Electronic configuration of iron

Iron is a one-of-a-kind element that exists both outside and inside us. Iron has 8 valence electrons and an electron configuration of 1s² 2s¹ 2p⁶ 3s² 3p⁶ 3d⁶ 4s², which means it has

• K shell – 2 electrons,

• L shell – 8 electrons,

• M shell – 14 electrons, and

• N shell – 2 electrons.

Significance of electronic configuration of Iron

Various properties of Iron can be explained using electronic configuration. Like, Iron is a silvery white metal that is ductile and malleable under normal conditions. Iron is a medium-activity metal that extracts hydrogen from water solutions of strong acids like HCl and sulphuric acid, resulting in the formation of iron salts. These can be explained by number of valence shell electrons in Iron.

What Function Does Electronic Configuration of Elements Play?

The chemical characteristics of elements are largely determined by their electronic arrangement. Despite their small size, electrons are responsible for determining the nature of the elements. They determine the valency, ionisation potential, ionisation enthalpy, chemical bonding, and practically all other chemical properties of the element. When an element lacks an electron, it is classified as an electron acceptor, and when it has an excess electron, it is classified as an electron giver. As a result, electrical configuration, like the electron, is a deciding factor.

Recommended topic video on (Electronic Configuration of First 30 Elements )

Some Solved Examples

Example 1:

Which law indicates about the pairing of electrons in the same orbital?

1) Newton’s first law

2) (correct) Hund’s rule

3) Aufbau principle

4) Pauli exclusion principle

Solution

Hund’s rule states that “pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital belonging to that subshell has got one electron each. It is singly occupied”.

Hence, the answer is the option (2).

Example 2:

Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to ______

1) (correct) 12

2) 11

3) 10

4) 9

Solution

The electronic configuration of V(Z= 23) is given as

$1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^3$

Thus, there are 12 electrons in the p-orbitals of Vanadium.

Hence, the answer is the option (1).

Example 3:

Identify the element for which electronic configuration in +3 oxidation state is $[\mathrm{Ar}] 3 \mathrm{~d}^5:$ :

1) Ru

2) Mn

3) Co

4) Fe

Solution

As we have learned,

Fe has an electronic configuration of $[\mathrm{Ar}] 4 \mathrm{~s}^2 3 \mathrm{~d}^6$

So, $\mathrm{Fe}^{3+}$ has an electronic configuration $[\mathrm{Ar}] 3 \mathrm{~d}^5$.

Hence, the answer is the option (4).

Conclusion

The electronic configuration of the first 30 elements in their ground state is mentioned above in this article. This provides information regarding the unpaired electrons in their outermost shell, which tells us about their chemical properties. The atoms having the same number of outermost shell electrons are present in the same group in modern periodic table.

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