Question

When forming cations of main group metals, first remove electrons from the ______ subshell and then from the ______ subshell.

A) s; p
B) p; d
C) d; f
D) f; s

Answer 1

When forming cations, main group metals lose electrons from the s subshell first, followed by the p subshell, thus the correct sequence is A) s; p.

Step-by-step explanation:

When forming cations of main group metals, first remove electrons from the s subshell and then from the p subshell. The correct answer is A) s; p.

Main group elements, which include group 1 and group 2 metals, lose their outermost s electrons first when they form cations. This can be remembered because the first two columns on the left side of the periodic table are known as the s block. After the s electrons are removed, if there is a need to remove more electrons to achieve a higher positive charge, electrons from the p subshell are then removed.

For example, Potassium (K) from group 1 will lose one electron from the 4s orbital to form K+: [Ar]4s0. Similarly, magnesium (Mg) from group 2 will lose two electrons from the 3s orbital to form Mg2+: [Ne]3s0.