Summary S-Block Elements – Complete Chemistry Revision Notes

Physical Properties 4Li + O2 2Li2O Physical Properties




air
Be & Mg are kinetically inert to O2 & H2O.




ds
ar
tow
M + O2 MO2 • Atomic & Ionic radii:




ity
• Atomic radii/Ionic Smaller than the
M + 2HCl MCl2 + H2




tiv




O2
radii: Increases with corresponding alkali




ac
Increase in atomic no.




O2
group, increases with




Re
• Ionization energy: 2Na + O2 Na2O2 increase in atomic
Decreases down the l
HC number.




O2
group.
• Density increases Chemical Chemical MO + H2O M(OH)2 (All basic except BeO)
• I.E.: I.E., higher than
H2O Properties H 2O corresponding
down the group.
2M + 2H2O 2M+ + 2OH- + H2 Properties alkali metals.
of alkali of alkaline
O
H2 metals earth 2

metals MO + O2 2MO
2M + H2 2MH NH
• Density: It decreases
• General electronic 3
NH




(x
3
from be to ca &




=
configuration:




)
,I
increases from Ca




Cl
Br
[Noble gas] ns1




,B
M + (x + y)NH3 [M(NH3)x]2+ + 2[e(NH3)y]- to Ra.




l,
• Belong to group 1 of




r, I
C
M + (x + y)NH3 [M(NH3)x] + [e(NH3)y]
+ - • General electronic




)
F,
the periodic table.




=
configuration
. low m.p. and b.p.




(x
[noble gas] ns2
. Forms ionic compound.
2M + X2 2Mx M + X2 MX2 . Forms Ionic compounds
except(Be.)


Alkali Metals Alkaline Earth Metals • Belong to Group 2 of
• Flame colour:
Li: Crimson red
6
Li
23
Na
39

K
85

Rb
132
Cs
223

Fr s-Block
The S-Block 9
Be
24
Mg
40
Ca
87
Sr
137
Ba
226

Ra
the periodic table.
• Flame colour:
Na: Yellow, K: Lilac
Rb: Red, Cs: Blue
• Low m.P and B.P.
3 11 19 37 55 87
Elements 4 12 20 38 56 88 Ca-Brick red,
Sr - crimson red,
Ba - Apple green.
• Higher M.P & B.P
than corresponding
• Obtained from sea Calcium alkali metals.
• Commonly known as Plaster
water. of Paris (POP). sulphate
Sodium
Anomalous behaviour of • It is Used in the • Prepared by heating gypsum hemihydrate
Chloride at 393 K. CaSO4, ½H2O
preparation of • Used for coating walls.
li is due to: (NaCl)
Na2O2 , NaOH and • Commonly known as
(a) Exceptionally small size of Na2CO3. Quick lime. Calcium
• Prepared by heating
it's atom and ion. lime stone.
Oxide
• Used to manufacture (CaO) Uses
(b) Absence of d orbital. • Commonly known as cement and dye stuffs.
baking soda. . Be is used to manufacture alloys.
• Prepared by saturating
Sodium a solution of • Ca in extraction of metals.
Important bicarbonate Na2CO3 with CO2.
Important
Biological importance
Compounds of (NaHCO3) • Used in Fire extinguisers • Commonly known as Slaked Compounds of • Mg-Al alloys are used in aircraft
of Na and K Calcium
and baking of cake. lime. Calcium construction.
Sodium • Prepared by adding water hydroxide
• Sodium ions participate in Cellular . Used in baking common to quick lime.
signals, transmission and regular food products. • Used in white washing etc. Ca(OH)2 • Ra is used in radio therapy.
flow of water across cell
membranes.
• K ions active many enzymes and
oxidise of glucose to produce • Commonly known as
ATP. Sodium washing soda.
• Commonly known as Biological importance of
carbonate • Prepared by solvay's Lime stone. Calcium
(Na2CO3-10H2O)
process. • Prepared by passing
Mg and Ca
USES carbonate
• Used for washing, CO2 through slaked lime.
(CaCO3)
• Used to manufacture
cleaning etc. • All enzymes that utilise
• Li is used to make alloys. paper etc. Anomalous behaviour of
• KCl is used as fertilizer. Beryllium is due to:- ATP in Phosphate transfer
• Commonly known as requires Mg as co-factor,
• Cs is used in devising photoelectric Sodium caustic soda.
• Prepared by electrolysis (a) Small Size chlorophyll contains Mg.
cells. hydroxide of Brine solution.
• Liquid Na metal is used as coolant (NaOH) • Used in preparation of (b) High Ionisation enthalpy
• Ca is present in bones and
in nuclear reactors. soap, paper etc.
(c) Absence of d-orbitals teeth.



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