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The s-Block Elements
Name the elements of group 1. Write their electronic configurations.
The metallic elements lithium (Li), sodium (Na), potassium(K), rubidium (Rb), caesium (Cs) and francium (Fr) constitute group 1 of the periodic table. Francium is a radioactive element. They are known as alkali metals because their hydroxides are strong alkalies or bases.
Electronic configuration: The atoms of alkali metals have one electron in s-orbital outside a noble gas core. Therefore, their general electronic configuration is:
[Noble gas]ns1 where n = 2 to 7
The electronic configurations of alkali metals are given below:
| Element | At No | Electronic configuration |
| Lithium (Li) | 3 | [He]2s1 |
| Sodium (Na) | 11 | [Ne] 3s1 |
| Potassium (K) | 19 | [Ar] 4s1 |
| Rubidium (Rb) | 37 | [Kr] 5s1 |
| Caesium (Cs) | 55 | [Xe] 6s1 |
| Francium (Fr) | 87 |
[Rb] 7s1 |
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Lithium has highest ionisation energy in group 1 elements, yet it is strongest reducing agent. Comment.
The softness of group 1 elements increases down the group with increasing atomic number. Give reason.
Which is the most reactive alkali metal and why?
Why alkali metals do not form M2+ ions?
Name the radio active element in group 1. How does it resemble with the remaining elements of the group?
Why alkali metals are normally kept in kerosene oil?
Why lithium cannot be stored in kerosene?
Why does lithium form complexes?
Why are alkali metal ions diamagnetic and colourless?
Why are alkali metals the most electropositive in nature?
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