Octet Rule - Chemical Bonding Video Lecture | Inorganic Chemistry

I want to talk to you guys about a basic
rule in chemistry called the octet rule
so we know that atoms love to be stable
and the way an atom can achieve
stability is by having a complete number
of electrons valence electrons in the
outer energy level these valence
electrons will allow atoms to have
different properties the octet rule
states that an atom will gain or lose
electrons to obtain eight electrons in
its outer shell
in other words elements want to reach an
electron configuration of the nearest
noble gas the word octet means a group
of eight for example an octopus is an
animal with eight legs
an octagon is a shape with 8 sides so
let's look at a model of an atom we know
that an atom has a nucleus where the
protons and neutrons are located around
the nucleus we know that there are
electron shells where all the electrons
are located the first electron shell in
an atom can hold two electrons maximum
the electrons in the outermost shell are
called valence electrons which determine
the properties of the atom the second
electron shell can hold a maximum of
eight electrons in this case the
electrons in the second electron shell
are called the valence electrons the
third electron shell can also hold a
maximum of eight electrons in this case
the electrons in the third electron
shell are called valence electrons and
so on so let's look at the element
lithium lithium is in Group one of the
periodic table and since it's in Group
one it has one electron in its outermost
shell
another example is an element that is in
group 16 of the periodic table it will
have six valence electrons elements in
the same column as Group 16 will also
have six valence electrons this is a
general way to figure out the number of
electrons foreign elements elements like
to be in their most stable electron
configuration so the easiest thing for
lithium to do is lose that one electron
in its outermost shell to obtain the
electron configuration of the noble gas
helium
helium is a very stable element because
of its electron configuration sodium
like lithium is also in Group 1 and has
one valence electron notice the lonely
valence electron in the third shell of
the atom this shell needs seven more
electrons to satisfy the octet rule but
the easiest thing for sodium to do is
lose that electron if it can and when it
does sodium will now have the electron
configuration of the noble gas neon now
let's look at chlorine chlorine is in
group 17 which indicates it has seven
valence electrons so looking at the
chlorine atom notice how the outermost
shell needs one more electron to satisfy
the octet rule and have eight electrons
to be stable that's why chlorine is a
very reactive element because it just
needs one more electron and when it does
it will have the stable electron
configuration of noble gas argon and
that is the octet rule