The
periodic
table
is
the
arrangement
of
the
chemical
____________________
.
For
years
,
scientists
have
used
the
elements'
chemical
and
____________________
properties
to
arrange
the
periodic
table
.
In
1829
,
German
scientist
Johann
Dobereiner
discovered
groups
of
three
elements
sharing
similar
properties
and
called
them
Dobereiner's
____________________
.
Because
many
elements
known
didn't
fit
into
a
triad
,
this
system
wasn't
useful
.
In
1864
,
British
chemist
John
Newlands
arranged
the
56
known
elements
by
____________________
atomic
weights
.
The
Newlands
____________________
,
like
musical
octaves
,
were
so
named
because
every
eighth
element
had
similar
properties
to
the
first
in
its
group
.
Unfortunately
,
this
system
also
fell
short
.
In
1869
,
Russian
chemist
Dmitri
____________________
examined
the
63
known
elements
and
arranged
them
by
atomic
____________________
AND
physical
/
chemical
____________________
,
thereby
creating
the
world's
first
periodic
table
.
It's
arranged
by
Mendeleev's
____________________
which
states
"
the
physical
and
chemical
properties
of
elements
are
a
periodic
____________________
of
their
atomic
masses
.
"
In
his
periodic
table
,
the
seven
horizontal
rows
are
called
____________________
and
the
eight
vertical
columns
are
called
____________________
.
Mendeleev's
table
had
some
flaws
(
ex
.
where
to
place
Hydrogen
,
etc
.
)
and
needed
some
improvements
.
Finally
,
in
1913
,
an
English
physicist
named
Henry
Moseley
discovered
that
the
____________________
____________________
is
the
most
fundamental
property
of
an
element
,
NOT
the
atomic
mass
.
This
helped
to
modify
Mendeleev's
periodic
law
into
"
____________________
____________________
____________________
.
"
It
states
"
the
chemical
and
physical
properties
of
elements
are
a
periodic
function
of
their
atomic
number
.
"
Using
this
law
,
the
modern
periodic
____________________
was
produced
.
