Video Transcript
Which of these statements explains
why atoms of neon do not form ionic bonds? (A) Atoms of neon have delocalized
electrons. (B) Atoms of neon must gain or lose
four electrons to form a stable octet in their outer shell. (C) Atoms of neon already have a
stable octet in their outer shell. (D) Atoms of neon form dense
metallic structures instead. Or (E) Atoms of neon share
electrons to form covalent structures.
Neon is an element to be found in
group 18 otherwise known as group eight of the periodic table. The atomic number of neon is
10. This means that an atom of neon
will contain 10 protons in its nucleus. And since atoms are by definition
neutral, we’ll need 10 electrons as well. So our atoms of neon consist of a
nucleus with a 10-plus charge surrounded by 10 electrons in an electron cloud. Ionic bonds are electrostatic
attractions between positively and negatively charged ions. Atoms can lose or gain electrons to
form positive or negative ions.
We need to look at the five
statements and find the one that accounts for the fact that atoms of neon do not
form ionic bonds. The first thing it will be helpful
to remember is that neon is one of the noble gases, which are well-known for not
forming any bonds at all, with some exceptions. However, generally speaking, neon
goes around as single atoms. Statement (A) suggests that atoms
of neon have delocalized electrons. When considering bonding, we
generally think about metallic bonding when we consider delocalized electrons. But neon, being a monatomic gas,
doesn’t have delocalized electrons, so we can dismiss this answer.
The next statement says that atoms
of neon must gain or lose four electrons to form a stable octet in their outer
shell. The outer shell is sometimes also
known as the valence shell. The word octet in this statement
should hint towards the octet rule, which tells us that atoms tend to react to
acquire eight electrons in their outer shell. To continue with this, we need to
put the electrons in our neon atom into their shells. The first electron shell can fit a
maximum of two electrons, leaving us with eight. And the second electron shell can
fit all those eight electrons and no more. So we’ve accounted for the
locations of all 10 electrons.
Eight electrons is an octet, and
the second electron shell for a neon atom is the outer shell. So we don’t need to lose or gain
electrons in this shell to form an octet. However, if, for instance, we were
dealing with atoms of silicon with electron configuration 2, 8, 4, we could lose
four electrons to have 2, 8 or gain four electrons to have 2, 8, 8. Statement (C) says that atoms of
neon already have a stable octet in their outer shell. This is true. The octet of electrons in the neon
atom is particularly stable, so we don’t see neon reacting to lose or gain electrons
and form ionic bonds.
However, just in case, let’s have a
look at the other two answers. We’ve already identified that neon
is nonmetallic. It’s a monatomic gas generally, so
the fourth answer is not correct. And atoms of neon won’t form
covalent structures and share electrons because they already have a full outer
shell. So the statement that explains why
atoms of neon do not form ionic bonds is that atoms of neon already have a stable
octet in their outer shell.
