Video Transcript
Halogens gain electrons when
forming bonds with most metals. Once an atom of fluorine has
reacted and formed a bond with a metal atom, how many electrons would have been
gained?
Atoms have a tendency to gain,
lose, or share electrons to attain a stable electronic configuration. An electronic configuration is
generally stable with two electrons in the K shell or eight electrons in other
shells.
This problem asks us about
fluorine. Atoms of fluorine have nine
electrons. This corresponds to two electrons
in the K shell and seven electrons in the L shell. Atoms of fluorine need to gain one
electron to attain a stable electronic configuration with eight electrons in the L
shell.
The number of electrons an atom
gains, loses, or shares when forming a bond, like described in this problem, is
called the valence. So atoms of fluorine have a valence
of one since atoms of fluorine have a tendency to gain one electron. But we didn’t need to know the
valence to answer this question. We only needed to know how many
electrons would be gained when an atom of fluorine reacts to form a bond. And we determined that atoms of
fluorine gain one electron.
