Chapter 2.3 Electronic Configuration

The following are the rules to be applied when filling electrons into orbitals of an atom, EXCEPT

• Aufbau principle

• Charles's Law

• Hund's rule

• Pauli's exclusion principle

The electronic configuration of an atom is 1s² 2s ² 2p⁴. The number of valence electrons in the atom is ...

• 8

• 6

• 10

• 2

What is the electronic configuration for Phosphorus atom ?

• 1s²2s²2p⁶3s²3p³

• 1s²2s²2p⁶3s²3p⁵

• 1s²2s²2p³

• 1s²2s²2p⁶3s²

Electrons occupy orbitals of the lowest energy first. Which of the following rules or principles states this?

• Balmer rule

• Hund's rule

• Aufbau principle

• Pauli's exclusion principle

Electrons are paired based on their spin directions, clockwise or anti clockwise. Which of the following is related to the above statement ?

• Hund's rule

• Pauli's exclusion principle

• Aufbau principle

• Heisenberg uncertainty principle

Which of the following statements is correct about the Figure 1 ?

• All the arrows should be pointing up

• In the 2p orbitals, there should be only one electron in the last two orbitals with the same spinning direction

• There is nothing incorrect with this diagram

Which of the following is the electronic configuration for Mg²⁺ ion?

• 1s² 2s² 2p⁶

• 1s² 2s² 2p⁶ 3s² 3p⁶

• 1s² 2s² 2p⁶ 3s² 3p²

• 1s² 2s² 2p⁶ 3s²

Which of the following statement is correct about Hund's rule ?

• Electrons must occupy the degenerate orbital with the same spin, before adding electrons with opposite spins to the same orbital

• Each electron will occupy the lowest energy orbital first

• A maximum of two electrons can occupy a single atomic orbital, only if the electrons have opposite spins

Which pair of ions have the same electronic configuration? ( Hint: more than one answer)

• Mg²⁺ and Al³⁺

• Al³⁺ and F^-

• Sc³⁺ and F^-