Write down the outermost electronic configuration of alkali metals. How will you justify their placement in group 1 of the periodic table?
Write down the outermost electronic configuration of alkali metals. How will you justify their placement in group 1 of the periodic table?
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1 Answer
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This is a Long Answer Type Questions as classified in NCERT Exemplar
The group 1 elements are called alkali metals which possess outermost electronic configuration as ns1 .All the elements that have same outermost electron configuration possess similar properties and are placed in the same group.
Atomic number
Symbol
Electronic Configuration
3
Li
1s2 2s1
[He]2s1
11
Na
1s2 2s2 2p6 3s2
[Ne]3S1
19
K
1s2 2s2 2p6 3s2 4s1
[Ar]4S1
37
Rb
1s2 2s2 2p6 3s2 3d10 4s2 4p6 5s1
[Kr]5S1
55
87
Cs
Fr
1s2 2s2 2p6 3s2 3d10 4s2 4p6 5d10 5s2 5p6 6s1
[Xe]6s1
[Rn]7s1
Similar Questions for you
Among isoelectronic monoatomic species, size is inversely proportional to atomic number. Hence among isoelectronic species Na? , O²? , N³? , F? (having the nearest noble gas configuration);
Order of size is Na? < F? < O²? < N³?
N³? has least atomic number hence the largest size
Electron gain enthalpy increases with electro negativity chlorine has higher electron gain enthalpy than fluorine (exception)
In isoelectronic species nuclear charge can be approximated as
Nuclear charge ≈ z / no. of electrons
Al³? Mg²? Na? F? O²? N³?
Nuclear Charge: 13/10 12/10 11/10 9/10 8/10 7/10
Minimum nuclear charge is in N³? and maximum is in Al³?
So order should be
Al³? < Mg²? < Na? < F? < O²? < N³?
(a) The element V has the highest first ionization enthalpy (? iH1) and positive electron gain enthalpy (? egH) and hence it is the least reactive element. Since inert gases have positive? egH, therefore, the element-V must be an inert gas. The values of? iH1, ? iH2 and? egH match that of He.
(b) The element II which has the least first ionization enthalpy (? iH1) and a low negative electron gain enthalpy (? egH) is the most reactive metal. The values of ? iH1, ? iH2 and? egH match that of K (potassium).
(c) The element III which has high fi
This is a Matching Type Questions as classified in NCERT Exemplar
i d + 48
ii a &n
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