Dr Inam Ul Haq Jazbi Periodic Properties of s-block, p-Block and d-Block Elements
s-block Elements (Definition & Electronic configuration)
Definition
The electropositive elements of group IA and IIA of periodic table are referred as s-block elements
because they are associated with ns1 and ns2 valence shell configuration respectively. Since valence
electron enters into s-orbital they are called s-block elements.
Name
1. Group IA include 6 elements; Li, Na, K, Rb, Cs, Fr. Francium is radioactive.
2. The IA group is also called Lithium Family being Lithium is the first member.
3. Group IA elements are called Alkali Metals because they yield strong alkalis when their oxides,
hydroxides or hydrides are dissolved in water which are completely soluble in water.
2Na + 2H2O 2NaOH + H2
Na2O + H2O 2NaOH
4. Group IIA include 6 elements; Be, Mg, Ca, Sr, Ba and Ra. Radium is radioactive.
5. The IIA group is also called Beryllium Family being Be is the first member.
6. Group IIA elements are called Alkaline Earth Metals because they and their compounds (CaCO 3) are
found abundance in earth crust and yield weak bases when their oxides, hydroxides and hydrides are
dissolved in water which are sparingly soluble in water.
CaO + H2O Ca(OH)2
Electronic Configuration of s-Block Element
Alkali Metals
= 1s2, 2s1 [He], 2s
1
3Li
= 1s2, 2s2 2p6, 3s1 [Ne], 3s
1
11Na
[Ar], 4s
2 2 6 2 6 1 1
19K = 1s , 2s 2p , 3s 3p , 4s
[Kr], 5s
2 2 6 2 6 2 10 6 1 1
37Rb = 1s , 2s 2p , 3s 3p , 4s , 3d , 4p , 5s
55Cs = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s1 [Xe], 6s1
Since, their valence shell configuration is ns1, so:
(i) Their principal oxidation state is +1 and they form monovalent cation.
(ii) They are placed in group IA only.
Property Li Na K Rb Cs
Atomic No (Z) 3 11 19 37 55
Electronic [He], 2s1 [Ne], 3s1 [Ar], 4s1 [Kr], 5s1 [Xe], 6s1
Configuration
Flame colouration Crimson red Golden yellow Pale violet Reddish violet Blue
Alkaline Earth Metals
4Be = 1s2, 2s2 [He], 2s2
12Mg = 1s2, 2s2 2p6, 3s2 [Ne], 3s2
2 2 6 2 6 2
20Ca = 1s , 2s 2p , 3s 3p , 4s [Ar], 4s2
38Sr = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2 [Kr], 5s2
56Ba = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2 [Xe], 6s2
Since, their valence shell configuration is ns2, so:
(i) Their principal oxidation state is +2 and they form divalent cation
(ii) They are placed in group IIA only.
Property Be Mg Ca Sr Ba
,Dr Inam Ul Haq Jazbi Periodic Properties of s-block, p-Block and d-Block Elements
, Dr Inam Ul Haq Jazbi Periodic Properties of s-block, p-Block and d-Block Elements
Difference between Alkali and Alkaline Earth Metals
Alkali Metals Alkaline Earth Metals
Valence shell electronic configuration and number of valence electrons and type of cation
They have ns1 valence shell configuration i.e. possess They have ns2 valence shell configuration i.e.
one valence electron. Thus they form monovalent possess two valence electrons. Thus they form
cation. divalent cation.
M M+ + 1e– M: M2+ + 2e–
Nature of hydroxides and oxides
They yield strong alkalies, which are completely They yield weak bases, which are sparingly soluble
soluble in water, when their oxides dissolve in water. in water, when their oxides dissolve in water.
Electropositive Character
They possess more electropositive character due to They possess less electropositive character due to
less E.N. values. large E.N. values.
Ionization potential
They have low 1st I.P. due to less nuclear attraction on They have much higher 1st I.P. due to more nuclear
valence electron due to large atomic size. attraction on valence electrons due to small atomic
size.
Atomic and ionic radii
Atomic radii and ionic radii of alkali metals are Atomic radii and ionic radii of alkaline earth metals
comparatively large due to less small nuclear charge. are much smaller due to high nuclear charge.
Magnetic behavior
They are all paramagnetic because of unpaired They are all diamagnetic because of paired
electrons. electrons.
Specific gravity
They are lighter than water. e.g. Their specific gravity They are heavier than water. e.g. Their specific
are; Li = 0.53, Na = 0.67 gravity are; Be = 1.8, Mg = 1.74
Hardness, melting and boiling points
They are relatively less dense and soft having very low They are relatively harder having high melting &
melting and boiling points due to less interatomic boiling points due to more interatomic interactions
interactions (due to large atomic radii). (due to small atomic radii & extra valence electrons).
Electrode potential and reducing power
They have relatively high electrode potential. So they They have relatively less electrode potential. So they
are more strong reducing agent. are less strong reducing agent.
Nature of carbonates, phosphates and sulphates
Their carbonates, phosphates, sulphates (except Li) Their carbonates, phosphates, sulphates are
are soluble in water. insoluble in water.
s-block Elements (Definition & Electronic configuration)
Definition
The electropositive elements of group IA and IIA of periodic table are referred as s-block elements
because they are associated with ns1 and ns2 valence shell configuration respectively. Since valence
electron enters into s-orbital they are called s-block elements.
Name
1. Group IA include 6 elements; Li, Na, K, Rb, Cs, Fr. Francium is radioactive.
2. The IA group is also called Lithium Family being Lithium is the first member.
3. Group IA elements are called Alkali Metals because they yield strong alkalis when their oxides,
hydroxides or hydrides are dissolved in water which are completely soluble in water.
2Na + 2H2O 2NaOH + H2
Na2O + H2O 2NaOH
4. Group IIA include 6 elements; Be, Mg, Ca, Sr, Ba and Ra. Radium is radioactive.
5. The IIA group is also called Beryllium Family being Be is the first member.
6. Group IIA elements are called Alkaline Earth Metals because they and their compounds (CaCO 3) are
found abundance in earth crust and yield weak bases when their oxides, hydroxides and hydrides are
dissolved in water which are sparingly soluble in water.
CaO + H2O Ca(OH)2
Electronic Configuration of s-Block Element
Alkali Metals
= 1s2, 2s1 [He], 2s
1
3Li
= 1s2, 2s2 2p6, 3s1 [Ne], 3s
1
11Na
[Ar], 4s
2 2 6 2 6 1 1
19K = 1s , 2s 2p , 3s 3p , 4s
[Kr], 5s
2 2 6 2 6 2 10 6 1 1
37Rb = 1s , 2s 2p , 3s 3p , 4s , 3d , 4p , 5s
55Cs = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s1 [Xe], 6s1
Since, their valence shell configuration is ns1, so:
(i) Their principal oxidation state is +1 and they form monovalent cation.
(ii) They are placed in group IA only.
Property Li Na K Rb Cs
Atomic No (Z) 3 11 19 37 55
Electronic [He], 2s1 [Ne], 3s1 [Ar], 4s1 [Kr], 5s1 [Xe], 6s1
Configuration
Flame colouration Crimson red Golden yellow Pale violet Reddish violet Blue
Alkaline Earth Metals
4Be = 1s2, 2s2 [He], 2s2
12Mg = 1s2, 2s2 2p6, 3s2 [Ne], 3s2
2 2 6 2 6 2
20Ca = 1s , 2s 2p , 3s 3p , 4s [Ar], 4s2
38Sr = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2 [Kr], 5s2
56Ba = 1s2, 2s2 2p6, 3s2 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2 [Xe], 6s2
Since, their valence shell configuration is ns2, so:
(i) Their principal oxidation state is +2 and they form divalent cation
(ii) They are placed in group IIA only.
Property Be Mg Ca Sr Ba
,Dr Inam Ul Haq Jazbi Periodic Properties of s-block, p-Block and d-Block Elements
, Dr Inam Ul Haq Jazbi Periodic Properties of s-block, p-Block and d-Block Elements
Difference between Alkali and Alkaline Earth Metals
Alkali Metals Alkaline Earth Metals
Valence shell electronic configuration and number of valence electrons and type of cation
They have ns1 valence shell configuration i.e. possess They have ns2 valence shell configuration i.e.
one valence electron. Thus they form monovalent possess two valence electrons. Thus they form
cation. divalent cation.
M M+ + 1e– M: M2+ + 2e–
Nature of hydroxides and oxides
They yield strong alkalies, which are completely They yield weak bases, which are sparingly soluble
soluble in water, when their oxides dissolve in water. in water, when their oxides dissolve in water.
Electropositive Character
They possess more electropositive character due to They possess less electropositive character due to
less E.N. values. large E.N. values.
Ionization potential
They have low 1st I.P. due to less nuclear attraction on They have much higher 1st I.P. due to more nuclear
valence electron due to large atomic size. attraction on valence electrons due to small atomic
size.
Atomic and ionic radii
Atomic radii and ionic radii of alkali metals are Atomic radii and ionic radii of alkaline earth metals
comparatively large due to less small nuclear charge. are much smaller due to high nuclear charge.
Magnetic behavior
They are all paramagnetic because of unpaired They are all diamagnetic because of paired
electrons. electrons.
Specific gravity
They are lighter than water. e.g. Their specific gravity They are heavier than water. e.g. Their specific
are; Li = 0.53, Na = 0.67 gravity are; Be = 1.8, Mg = 1.74
Hardness, melting and boiling points
They are relatively less dense and soft having very low They are relatively harder having high melting &
melting and boiling points due to less interatomic boiling points due to more interatomic interactions
interactions (due to large atomic radii). (due to small atomic radii & extra valence electrons).
Electrode potential and reducing power
They have relatively high electrode potential. So they They have relatively less electrode potential. So they
are more strong reducing agent. are less strong reducing agent.
Nature of carbonates, phosphates and sulphates
Their carbonates, phosphates, sulphates (except Li) Their carbonates, phosphates, sulphates are
are soluble in water. insoluble in water.
