classification of elements
and
Periodic properties
Periodic table is arrangement of chemical
elements in a tabular form on basis
of their properties facilitates which
the
systematic study of properties of the
elements
c
Mendeleev's periodic Law physical and
The
chemical properties
of elements are periodic functions of their
atomic masses
Drawbacks
No place for isotopes
In few places element having more atomic mass
was placed
before element having lower
atomic mass
No
unique place for H
But periodic table
Mendeleev's was challenged
by Moseley's experiment
,Moseley's experiment
Basis of modern periodic table
He bombarded energetic electrons
high speed
on different heavy metal surfaces and
obtained X
rays
He observed a systematic mathematical
relation between the frequency
of emitted
x
rays and atomic no of metals used
A
Tu Tu
so
Atomic mass Atomic no
M Z
JJ a 2 b
Moseley's eqn
D frequency of emitted x rays
2 atomic no element
a b constants
JV X Z
, He
thereby showed that the atomic no
is a more fundamental property of an
element than its atomic mass
Derivation of Moseley's egh from Bohr's model
not for school
o
Entente
replacing 2 by Zeffective
effectihagngewbat.Eaeotewt.nuIed
2JT2me4 2
U Zeff
73 nta
D 2T2me4 Z
a
F Wiest.to e e repulsion
for ka line 2
nns const
2
D 2thYe4_ L b
t
const of
JJ a Z b
, Modern Periodic Law The physical and
chemical properties
of elements are periodic functions of
their atomic numbers
i e elements are arranged in order
if
of increasing atomic numbers the elements
with similar properties are repeated
after certain
regular intervals
Modern periodic law is essentially the
consequence of periodic variation in
electronic configuration
Long Form of modern periodic table
Total no
of known elements 118
Horizontal rows of periodic table are
Called Periods Total no of periods _7
vertical columns of periodic table are
Called Groups families
Total no of Groups 18
Total no
of blocks 4 S Pid f
and
Periodic properties
Periodic table is arrangement of chemical
elements in a tabular form on basis
of their properties facilitates which
the
systematic study of properties of the
elements
c
Mendeleev's periodic Law physical and
The
chemical properties
of elements are periodic functions of their
atomic masses
Drawbacks
No place for isotopes
In few places element having more atomic mass
was placed
before element having lower
atomic mass
No
unique place for H
But periodic table
Mendeleev's was challenged
by Moseley's experiment
,Moseley's experiment
Basis of modern periodic table
He bombarded energetic electrons
high speed
on different heavy metal surfaces and
obtained X
rays
He observed a systematic mathematical
relation between the frequency
of emitted
x
rays and atomic no of metals used
A
Tu Tu
so
Atomic mass Atomic no
M Z
JJ a 2 b
Moseley's eqn
D frequency of emitted x rays
2 atomic no element
a b constants
JV X Z
, He
thereby showed that the atomic no
is a more fundamental property of an
element than its atomic mass
Derivation of Moseley's egh from Bohr's model
not for school
o
Entente
replacing 2 by Zeffective
effectihagngewbat.Eaeotewt.nuIed
2JT2me4 2
U Zeff
73 nta
D 2T2me4 Z
a
F Wiest.to e e repulsion
for ka line 2
nns const
2
D 2thYe4_ L b
t
const of
JJ a Z b
, Modern Periodic Law The physical and
chemical properties
of elements are periodic functions of
their atomic numbers
i e elements are arranged in order
if
of increasing atomic numbers the elements
with similar properties are repeated
after certain
regular intervals
Modern periodic law is essentially the
consequence of periodic variation in
electronic configuration
Long Form of modern periodic table
Total no
of known elements 118
Horizontal rows of periodic table are
Called Periods Total no of periods _7
vertical columns of periodic table are
Called Groups families
Total no of Groups 18
Total no
of blocks 4 S Pid f
