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Group 1: Physical Properties(in Hindi)
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In this session we have covered group 1 of S-Block elements.

Anmol Sharma is teaching live on Unacademy Plus

Anmol Sharma
||MBBS||Main Aim to be REAL i.e Redefining Education and Learning. QED method Teaching i.e Quite Easily Done Youtube:- QED Zone.

U
Unacademy user
Zm
u said pyq's frm yr 2005..... are you sure
Tanya Bhatia
2 months ago
Yes
Zm
Zaidi mir
2 months ago
ok THANKS a ton we are eagerly waiting for this....
why other elements not show photoelectric effect other than K and Cs?
P
Sir bp me koi bhi exception nhi a
sir thq so much......i am feeling so unlucky that i got this videos so late. yr explanation is just........awesome....! lots of thq.
  1. S-BLOCK NEET/AlIMS/JIPMER - Anmol Sharma


  2. S-BLOCK INTRODUCTION The elements in which the last electron enters the outermost s-orbital are called s-block elements. . The group 1 and 2 of periodic table belong to the s-block Group 1 of the Periodic Table consists of the elements: lithium, sodium, potassium, rubidium, caesium and francium. Group 2 include beryllium, magnesium, calcium, strontium, barium and radium.


  3. Group 1 (1) The Elements: are Li, Na, K, Rb, Cs Fr (Radioactive: ty2 of Fr233 21 minutes) group-I elements are called alkali metals because they form hydroxides on reaction with water, which are alkaline in nature. (2) Outer Electronic configuration: ns1 (3) Atomic and Ionic radii L1 < Na < K < Rb < Cs. Increase down the group, because value of n(principal quantum number) increases. (4) Density L < K < Na < Rb < Cs. (5) Ionization Energy Li> Na> K> Rb > Cs. As size increases, I. E. decreases down the group (so Cs have lowest I. P.) Note: This is self created content for educational purpose only


  4. (6) Hardness and melting points/boiling points These metals are very soft and can be cut with a knife. Litium is harder than any other alkali metal The hardness depends upon cohesive energy M. P. Li Na> K> Rb> Cs B, P. Li > Na > K > Cs > Rb (7) Electropositive character or metallic character Alkali metals are strongly electropositive and metallic. Down the group electropositive nature increase so metallic nature also increases i.e., M M+ + e- 1 Metallic Nature : Electropositive character Li< NaKRb<Cs. Note: This is self created content for educational purpose only


  5. (8) Oxidation state Show +1 oxidation state because by loosing one electron they get stable noble gas configuration (9) Photoelectric effect The phenomenon of emission of electrons when electromagnetic rays strikes against them is called photoelectric effect Alkali metal have low I. P. so show photoelectric effect. Cs and K are used in photoelectric cells Note: This is self created content for educational purpose only


  6. THANK YOU