Exercise 3 | Quantum Theory and Atomic Structure

What is the electron configuration of sulfur (Z = 16)?

What is most likely ion formed from sulfur? What is its electron configuration?

What is the electron configuration of Fe2+ (Fe: Z = 26)?

sulfur: Z = 16 ⇒ 16 electrons
electron configuration: 1s22s22p63s23p4


The closest noble gas to sulfur is argon (1s22s22p63s23p6)
Sulfur needs to gain 2 electrons to have the same electronic configuration than argon
The most likely ion formed from sulfur is S2- and its electronic configuration is 1s22s22p63s23p6


iron: Z = 26 ⇒ 26 electrons
electron configuration: 1s22s22p63s23p64s23d6
Fe2+ ⇒ loss 2 electrons ⇒ electron configuration: 1s22s22p63s23p64s03d6