In our next section we're gonna talk
about the periodic table can offer and
look into the periodic
properties of the elements.
So quantum mechanics
not only describes
the electronic
structure of the atom,
it also explains
the arrangement
of the periodic table.
And there are roughly 118
elements in the periodic table.
So to find some order,
There is a need,
to classify, the elements.
And back in 1869,
the periodic law was proposed,
By Mendeleev and Myer and
basically what these
guys did is they said
the following,
if the elements are listed
in order of increasing
atomic weight,
a certain number of
properties repeat
periodically.
Now there are some exceptions to this.
For example, if you look at potassium and
argon, if you look at the periodic table,
they are not ordered based
on the atomic weight.
So because of this.
Elements, Are arranged,
Based on, Atomic number.
And a tabular arrangement of the periodic
law is called the periodic table.
And Mendeleev was given credit for
this because when he was listing all
the elements back in 1869,
not all the elements existed yet.
And he left gaps for
the elements that weren't discovered yet.
So we can classify and
kinda describe the various trends
that are shown in the periodic table.
If we look at the horizontal
groups in the periodic table,
we refer to these as periods.
And the vertical groups
in the periodic we refer to
as groups or families.
And elements within
a particular group
have the same
properties.
So we're going to look into
the various ways that we can
group elements in the Periodic Table and
look into the trends that we'll
observe for these particular groups.
