Which of the following ion can have the electronic configuration 1s2 2s2 2p6 3s2 3p6 3d6

Which of the following ion can have the electronic configuration 1s2 2s2 2p6 3s2 3p6 3d6 Correct Answer Fe²⁺

The correct answer is Fe²⁺

Concept:

• Electronic configuration filled according to the Aufbau principle.
• Aufbau Principle:
  • It states that electrons are filled into atomic orbitals in the increasing order of orbital energy levels.
  • The order of energy level is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, and so on.

[ alt="DPT Aufbau 1" principle src="https://www.simply.science/images/content/chemistry/structure_of_matter/dev_of_periodic_table/conceptmap/DPT_Aufbau_1.gif" style="height: 240px; width: 300px; border-width: 1px; border-style: solid;">

Explanation:

• Electronic configuration of different ions and elements.
  • Fe - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
  • Fe²⁺- 1s2 2s2 2p6 3s2 3p6 3d⁶
  • Fe³⁺-  1s2 2s2 2p6 3s2 3p6 3d5
  • Cr - 1s²2s²2p⁶3s²3p⁶4s¹3d⁵

Notes:

• In this question, major confusion is between the Cr and Fe²⁺
• Because both have the same number of electrons.
• But we have to remove an electron from outer shells when we are converting it into ions.
• While chromium is in the ground state so it has a stable electronic configuration with 4s13d5.