The electronic configuration for an
atom of neon is shown below. Why do atoms of neon not usually
form ions? (A) Neon is neither a metal or a
nonmetal. (B) Neon exists as a gas, and gases
do not form ions. (C) Atoms of neon already have a
full outer shell. (D) The nucleus of neon atoms
contains too many neutrons. Or (E) atoms of neon lose a proton
to form atoms of fluorine instead.
The diagram we are given shows the
electronic configuration of neon. The electrons of an atom are found
outside of the nucleus in energy levels. The numbers on the bottom of the
diagram indicate the number of electrons in each energy level. Neon has two electrons in the first
energy level and eight electrons in the second energy level. The element neon is a noble gas,
which is a nonmetal.
The question asks why atoms of neon
do not form ions. Let’s consider the formation of
ions. The formation of a positive ion
generally occurs when metal atoms lose electrons. The formation of a negative ion
generally occurs when a nonmetal atom gains electrons. Atoms form ions in order to have a
full outer shell or, in other words, a full outer energy level. Neon’s electronic configuration
already has a full outer shell. This stable configuration is often
referred to as a noble gas configuration. Noble gases already have full outer
shells that other atoms strive to have. We can see then that answer choice
(C) is correct.
Therefore, atoms of neon do not
usually form ions because they already have a full outer shell.