Question

simple chemical reactions online practice
complete this assessment to review what youve learned. it will not count toward your grade.
use the periodic table to answer the question.
which element has the electron configuration of argon (ar) when it has a stable electron configuration?
(1 point)
o bromine (br)
o oxygen (o)
o magnesium (mg)
o potassium (k)
check answer remaining attempts: 3

Explanation:

Step1: Recall argon's electron configuration

Argon (Ar) has an electron configuration of \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\). It has 18 electrons.

Step2: Analyze each element's ion - electron configuration

• Bromine (Br): Bromine has 35 electrons. When it gains one electron to form \(Br^{-}\), it has \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}\) (36 electrons), not like Ar.
• Oxygen (O): Oxygen has 8 electrons. When it gains two electrons to form \(O^{2 -}\), it has \(1s^{2}2s^{2}2p^{6}\) (10 electrons), not like Ar.
• Magnesium (Mg): Magnesium has 12 electrons. When it loses two electrons to form \(Mg^{2+}\), it has \(1s^{2}2s^{2}2p^{6}\) (10 electrons), not like Ar.
• Potassium (K): Potassium has 19 electrons. When it loses one electron to form \(K^{+}\), it has \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\) (18 electrons), same as Ar.

Answer:

Potassium (K)