s-block Elements PPT Chemistry Class 12

 Page 1


1
S-BLOCK 
ELEMENTS
The s-Block Element
Page 2


1
S-BLOCK 
ELEMENTS
The s-Block Element
2
Group I Elements (Alkali Metals)
They have similar chemical properties. They are soft metals 
with fixed O.N. = +1 in their compounds.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N. ?H
hyd
of 
cation
Li He 2s
1
1.23 0.60 520 181 0.54 1.0 -519
Na Ne 3s
1
1.57 0.95 496 98 0.97 0.9 -406
K Ar 4s
1
2.03 1.33 419 63 0.86 0.8 -322
Rb Kr 5s
1
2.16 1.48 403 39 1.53 0.8 -293
Cs Xe 6s
1
2.35 1.69 375 29 1.87 0.7 -264
Fr Rn 7s
1
-- 1.76 -- 27 -- 0.7 --
Page 3


1
S-BLOCK 
ELEMENTS
The s-Block Element
2
Group I Elements (Alkali Metals)
They have similar chemical properties. They are soft metals 
with fixed O.N. = +1 in their compounds.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N. ?H
hyd
of 
cation
Li He 2s
1
1.23 0.60 520 181 0.54 1.0 -519
Na Ne 3s
1
1.57 0.95 496 98 0.97 0.9 -406
K Ar 4s
1
2.03 1.33 419 63 0.86 0.8 -322
Rb Kr 5s
1
2.16 1.48 403 39 1.53 0.8 -293
Cs Xe 6s
1
2.35 1.69 375 29 1.87 0.7 -264
Fr Rn 7s
1
-- 1.76 -- 27 -- 0.7 --
3
Group II Elements (Alkaline Earth Metals)
Mg and Ca are the most abundant elements and Ra is the most 
scarce element which is unstable and radioactive.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N.
?H
hyd
of 
cation
1st 2nd
Be He 2s
2
0.90 0.31 900 1760 1277 1.85 1.5 -2494
Mg Ne 3s
2
1.36 0.65 737 1450 650 1.74 1.2 -1921
Ca Ar 4s
2
1.74 0.99 590 1150 838 1.55 1.0 -1577
Sr Kr 5s
2
1.91 1.13 548 1060 768 2.60 1.0 -1443
Ba Xe 6s
2
1.98 1.35 502 965 714 3.50 0.9 -1305
Ra Rn 7s
2
-- 1.40 5.9 979 700 5.00 0.9 --
Page 4


1
S-BLOCK 
ELEMENTS
The s-Block Element
2
Group I Elements (Alkali Metals)
They have similar chemical properties. They are soft metals 
with fixed O.N. = +1 in their compounds.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N. ?H
hyd
of 
cation
Li He 2s
1
1.23 0.60 520 181 0.54 1.0 -519
Na Ne 3s
1
1.57 0.95 496 98 0.97 0.9 -406
K Ar 4s
1
2.03 1.33 419 63 0.86 0.8 -322
Rb Kr 5s
1
2.16 1.48 403 39 1.53 0.8 -293
Cs Xe 6s
1
2.35 1.69 375 29 1.87 0.7 -264
Fr Rn 7s
1
-- 1.76 -- 27 -- 0.7 --
3
Group II Elements (Alkaline Earth Metals)
Mg and Ca are the most abundant elements and Ra is the most 
scarce element which is unstable and radioactive.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N.
?H
hyd
of 
cation
1st 2nd
Be He 2s
2
0.90 0.31 900 1760 1277 1.85 1.5 -2494
Mg Ne 3s
2
1.36 0.65 737 1450 650 1.74 1.2 -1921
Ca Ar 4s
2
1.74 0.99 590 1150 838 1.55 1.0 -1577
Sr Kr 5s
2
1.91 1.13 548 1060 768 2.60 1.0 -1443
Ba Xe 6s
2
1.98 1.35 502 965 714 3.50 0.9 -1305
Ra Rn 7s
2
-- 1.40 5.9 979 700 5.00 0.9 --
4
Atomic and ionic radius
Atomic radius and ionic radius increase
An addition of one more shell; ENC decrease
Page 5


1
S-BLOCK 
ELEMENTS
The s-Block Element
2
Group I Elements (Alkali Metals)
They have similar chemical properties. They are soft metals 
with fixed O.N. = +1 in their compounds.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N. ?H
hyd
of 
cation
Li He 2s
1
1.23 0.60 520 181 0.54 1.0 -519
Na Ne 3s
1
1.57 0.95 496 98 0.97 0.9 -406
K Ar 4s
1
2.03 1.33 419 63 0.86 0.8 -322
Rb Kr 5s
1
2.16 1.48 403 39 1.53 0.8 -293
Cs Xe 6s
1
2.35 1.69 375 29 1.87 0.7 -264
Fr Rn 7s
1
-- 1.76 -- 27 -- 0.7 --
3
Group II Elements (Alkaline Earth Metals)
Mg and Ca are the most abundant elements and Ra is the most 
scarce element which is unstable and radioactive.
Electronic 
configuration
Atomic 
radius (Å)
Ionic 
radius
I.E. M.P. Density E.N.
?H
hyd
of 
cation
1st 2nd
Be He 2s
2
0.90 0.31 900 1760 1277 1.85 1.5 -2494
Mg Ne 3s
2
1.36 0.65 737 1450 650 1.74 1.2 -1921
Ca Ar 4s
2
1.74 0.99 590 1150 838 1.55 1.0 -1577
Sr Kr 5s
2
1.91 1.13 548 1060 768 2.60 1.0 -1443
Ba Xe 6s
2
1.98 1.35 502 965 714 3.50 0.9 -1305
Ra Rn 7s
2
-- 1.40 5.9 979 700 5.00 0.9 --
4
Atomic and ionic radius
Atomic radius and ionic radius increase
An addition of one more shell; ENC decrease
5
?1 Compare the atomic radius of alkali and 
alkaline earth metals
Alkali metals > alkaline earth metals because
Increase in nuclear charge > increase in shielding 
effect
ENC increases and electron experience a larger 
nuclear attraction.