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can you please give me detailed account of physical properties of all groups in p- block and s- block

can you please give me detailed account of physical properties of all groups in p- block and s- block

Grade:12

1 Answers

Vikas TU
14149 Points
4 years ago
All alkali metals have one electron in the s-sub shell. Due to the presence of only one electron in the outermost shell, they are highly reactive so as to obtain an octet configuration. Due to the presence of similar electronic configuration, all the elements show similarity in their properties.
 
  • Physical state: all the elements exist as silvery white, soft and light metals. These are considered as metals due to very low ionisation energies. These elements are malleable i.e. can be compressed into sheets and are also ductile i.e. they can be drawn in to wires. They are lustrous when freshly cut. But, the lustre tarnishes very easily upon exposure to air.
  • Atomic radius:as we know alkali metals are the largest elements of the corresponding periods. Atomic radius increases from lithium to Francium as we move down the period.
  • Density:density increases as we move from Li to Fr. But, an anomaly exists in case of sodium and potassium where K is lighter than Na. Li is the lightest metal among all the metals. Li, Na and K are lighter when compared to water.
  • Melting and Boiling points:due to the presence of large atomic radius, all these elements bond very weakly at the time of forming crystals. Due to weak inter-atomic bonding, all these elements have very low melting and boiling points. The melting and boiling points decrease as we move down from Li to Cs.
  • Ionisation Energy:due to less attraction of the nucleus on the outer most electrons, the outermost electron of all these elements can be very easily removed. Hence, these elements have very low ionisation energy. It decreases as we move down the group from Li to Cs.
  • Electropositive Character:due to low ionisation energy, alkali elements lose the electrons very easily. Hence, they can be said as strongly electropositive. The electropositive character increases as we move down the group from Li to Cs. Due to their strong electropositive nature, they emit electrons when exposed to light. This effect is termed as photo-electric effect. These elements are greatly used in photoelectric cells. As caesium and potassium are highly electropositive when compared to other elements, they are greatly used in the photoelectric cells when compared to other alkali metals.
  • Oxidation State:as alkali metal atoms have only one electron in the valence shell, they exhibit an oxidation state of +1. By losing one electron, these alkali metals form a unipositive ion that has a noble gas configuration. Hence, it is very difficult to remove an electron from these metal ions resulting in very high second ionization energies.
  • Electro negativity:they show very less tendency to attract electrons i.e. very low electronegativity. Electronegativity decreases from Li to Cs.
 

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