Answer:
Ca: [Ar] 4s²
Pm : [Xe} 6s² 4f⁵
Explanation:
The electronic configuation of an element in noble gas notation is written by giving the symbol of the nearest noble gas that is present in the period above it in the periodic table, followed by the electronic configuration of the remaining electrons.
For Ca the atomic no is 20
It is in 4th period.
The electronic configuration of Ca is 1s²2s²2p⁶3s²3p⁶4s²
1s²2s²2p⁶3s²3p⁶ represents the electronic congiguation of Ar with completely filled valence shell. So we can represent electronic configuration of Ca as [Ar] 4s².
The atomic no. of Promethium,Pm is 61. It's electronic configuration is
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f⁵
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶ is the configuration of the noble gas Xe . So we can represent electronic configuration of Pm as
[Xe} 6s² 4f⁵
