Question

define afbau principle​

Answer 1

Explanation:

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The aufbau principle, from the German Aufbauprinzip, also called the aufbau rule, states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s subshell is filled before the 2s subshell is occupied.

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Answer 2

Aufbau rule or Principle

•   The word 'aufbau' in German means 'building up'. The building up of orbitals means the filling up of orbitals with electrons
•    It states that in ground state of atom, the orbitals are filled in increasing order of their energies.
•    So electrons first occupy the lowest energy orbital available to them and enter into higher energy orbitals only after the lower energy orbitals are filled as per Pauli Exclusion principle & Hund Rule
•    Now we know that energy of a given orbital depends upon effective nuclear charge and different type of orbitals are affected to different extent. So there is no single ordering of energies of orbitals which will be universally correct for all atoms
•    But Following ordering can be used to predict the configuration of electrons in atom
•    1s, 2s ,2p, 3s ,3p ,4s ,3d ,4p, 5s,4d,5p,4f,5d,6p