Electronic Configuration | Definition, Explanation, Filling of Orbitals | Examples

The electronic configuration is the arrangement of electrons in the atomic orbitals of an atom. It is used to predict the chemical and physical properties of a substance. The electronic configuration is determined by the number of electrons in the atom, which is equal to the number of protons in the nucleus.

The basics of electronic configuration:

The electronic configuration is a way of describing the distribution of electrons in an atom or molecule in terms of their energy levels, subshells, and orbitals.

Electrons occupy the lowest energy levels available to them.
The number of electrons in an atom is equal to the number of protons in the nucleus.

Shells:

The electrons in an atom are arranged in shells, which are energy levels surrounding the nucleus. The first shell is the closest to the nucleus and can hold up to 2 electrons, the second shell can hold up to 8 electrons, and the third and outermost shell can hold up to 18 electrons.

Subshells:

Within each shell, electrons are further divided into subshells. Subshells are designated by letters (s, p, d, f) and indicate the shape of the orbital that the electrons occupy. The s subshell is spherical in shape and can hold up to 2 electrons, the p subshell is dumbbell-shaped and can hold up to 6 electrons, the d subshell is more complex in shape and can hold up to 10 electrons, and the f subshell is the most complex shape and can hold up to 14 electrons.

Several principles govern the electronic configuration of atoms:

Aufbau Principle:

The Aufbau Principle states that electrons fill the lowest energy levels first and proceed to fill higher energy levels as necessary. This means that electrons fill shells and subshells in order of increasing energy, starting with the 1s subshell and proceeding through the 4f subshell.

Pauli Exclusion Principle:

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of quantum numbers. This means that each electron in an atom must have a unique set of values for the four quantum numbers (n, l, ml, ms).

Hund’s Rule:

Hund’s Rule states that when electrons occupy degenerate orbitals (orbitals of the same energy), they will align in such a way that the number of electrons with the same spin is maximized. This means that electrons will occupy the same subshell one at a time before a second electron is added with the opposite spin.

The above principles are used to predict the electronic configuration of an atom and the chemical properties that are associated with it.

Additionally, there is a principle called Madelung’s rule which is used to predict the electronic configurations of ions. According to this principle, when an ion is formed, the electrons are removed from the highest energy subshell first, instead of the lowest energy subshell as in the case of the Aufbau principle.

Examples of electronic configurations:

• Carbon (C): 1s² 2s² 2p²
• Oxygen (O): 1s² 2s² 2p⁴
• Neon (Ne): 1s² 2s² 2p⁶

• Multiple choice questions to test understanding of electronic configurations and the principles that govern them.
• Fill-in-the-blank questions to test knowledge of specific electronic configurations of elements.
• Matching exercises to test understanding of the relationship between electronic configurations and chemical properties.
  

  Electronic Configuration

  
  

It’s important to keep in mind that this is general information and may vary depending on the context and the level of detail required.