Name: Electronic Arrangement of s-block Elements
Uploaded: 2019-07-19
Duration: 24 min 8 s
Description: Do you know how to write the electronic configuration of s-block elements? Is there any similarity in the electronic configuration of all the members of the...

Question

Explain any two of the following: Which is the most reactive metal of alkali metals and why?

Accepted Answer

Caesium is the most reactive among the alkali metals. The alkali metals exhibit high chemical reactivity. This is due to their low ionization energies and low heat of atomisation. As the value of ionisation energy decreases down the group from $Li$ to $Cs$ , the reactivity of alkali metals increases from $Li$ to $Cs$ .

Alkali metals have the lowest ionization energy in each period. Within the group, the ionization energies of alkali metals decrease down the group. The atoms of alkali metals are largest in their respective periods and therefore the valence electrons, are loosely held by the nucleus.By losing the valence electrons, they acquire stable noble gas configurations. This accounts for their case to lose electrons and hence they have low ionization energies. On moving down the group, the atomic size increases and the magnitude of screening effect (number of inner shells) also increases and consequently, the ionization energy decreases down the group. Thus, the alkali metals exhibit high chemical reactivity. The alkali metals are highly reactive towards the more electronegative elements such as oxygen and halogens.

Explain any two of the following: Which is the most reactive metal of alkali metals and why?

Important Questions on s-Block Elements:Alkali and Alkaline Earth Metals. Alkali Metals:(Group 1)

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