Flashcards for JEE Chemistry - s-block elements Class 12

 Page 1


s-block elements
Flash cards
Page 2


s-block elements
Flash cards
Introduction
(a) Elements of group 1 (or I A) and 2 (or II A) are known as 
s-block elements.
(b) General electronic configurations are
Group 1 [Inert gas]ns
1
Alkali metals
Group 2 [Inert gas]ns
2
Alkaline Earth metals
Page 3


s-block elements
Flash cards
Introduction
(a) Elements of group 1 (or I A) and 2 (or II A) are known as 
s-block elements.
(b) General electronic configurations are
Group 1 [Inert gas]ns
1
Alkali metals
Group 2 [Inert gas]ns
2
Alkaline Earth metals
Physical properties of s-block elements 
(Continued)
Property : Physical state
Alkali metal
(a) All are silvery white
(b) Light soft, malleable and ductile metals with metallic 
luster
(c) Both are diamagnetic and colourless
Alkaline earth metal
(a) All are grayish white
(b) Relatively harder
Page 4


s-block elements
Flash cards
Introduction
(a) Elements of group 1 (or I A) and 2 (or II A) are known as 
s-block elements.
(b) General electronic configurations are
Group 1 [Inert gas]ns
1
Alkali metals
Group 2 [Inert gas]ns
2
Alkaline Earth metals
Physical properties of s-block elements 
(Continued)
Property : Physical state
Alkali metal
(a) All are silvery white
(b) Light soft, malleable and ductile metals with metallic 
luster
(c) Both are diamagnetic and colourless
Alkaline earth metal
(a) All are grayish white
(b) Relatively harder
Physical properties of s-block elements 
(Continued)
Property : Flame colour
Alkali metal
(a) Both produces characteristic colour in Bunsen flame due to 
easy excitation of electron to higher energy levels.
(b) Characteristic flame colours are
Li – Crimson, Na – Golden Yellow, K – Pale violet, Rb and 
Cs – Violet
(c) Energy released
Li
+
< Na
+
< K
+
< Rb
+
< Cs
+
(d) The flame energy causes an excitation of the outermost 
electron which on reverting back to its initial position gives out 
the absorbed energy as visible light
Page 5


s-block elements
Flash cards
Introduction
(a) Elements of group 1 (or I A) and 2 (or II A) are known as 
s-block elements.
(b) General electronic configurations are
Group 1 [Inert gas]ns
1
Alkali metals
Group 2 [Inert gas]ns
2
Alkaline Earth metals
Physical properties of s-block elements 
(Continued)
Property : Physical state
Alkali metal
(a) All are silvery white
(b) Light soft, malleable and ductile metals with metallic 
luster
(c) Both are diamagnetic and colourless
Alkaline earth metal
(a) All are grayish white
(b) Relatively harder
Physical properties of s-block elements 
(Continued)
Property : Flame colour
Alkali metal
(a) Both produces characteristic colour in Bunsen flame due to 
easy excitation of electron to higher energy levels.
(b) Characteristic flame colours are
Li – Crimson, Na – Golden Yellow, K – Pale violet, Rb and 
Cs – Violet
(c) Energy released
Li
+
< Na
+
< K
+
< Rb
+
< Cs
+
(d) The flame energy causes an excitation of the outermost 
electron which on reverting back to its initial position gives out 
the absorbed energy as visible light
Physical properties of s-block elements 
(Continued)
Property : Flame colour
Alkaline earth metal
(a) Be and Mg do not show any colour as their electrons are 
more strongly bound.
(b) Ca – Brick red, Sr – Crimson
Ba–apple green, Ra – Crimson
(c) Be and Mg atoms due to their small size, bind their 
electrons more strongly because of higher effective nuclear 
charge. Hence these posses high excitation energy and are not 
excited by the flame energy and do not show any colour.