The s-block elements are characterised by their larger atomic sizes, lower ionisation enthalpies, invariable +1 oxidation state and solubilities of their oxosalts. In the light of these features describe the nature of their oxides, halides and oxosalts.

The s-block elements are characterised by their larger atomic sizes, l

1.	The s-block elements are characterised by their larger atomic sizes, lower ionisation enthalpies, invariable +1 oxidation state and solubilities of their oxosalts. In the light of these features describe the nature of their oxides, halides and oxosalts.
Answer» Solution : The atom of alkali metals have large size and due to this they readily form cations and so their compounds are ionic in nature. Alkali metals have +1 oxidation state and give ionic compounds. Alkali metals give three TYPES of oxides - Normal oxides`(M_(2)O)`, Peroxide `(M_(2)O_(2))` and Super oxides`(MO_(2))`. Basic character of normal oxides increases from `Li_(2)O` to `Cs_(2)O` due to increase in their ionic character. Halides of alkali metals MX are also ionic except Lix, which is covalent because of small size and high polarizing power. Oxosalts: All alkali metals from solid carbonates of general formula `M_(2)C0_(3)`. Carbonates are STABLE except `Li_(2)CO_(3)` due to high polarising capacity of `Li^(+)`which is unstable and decomposes. All the alkali metals (except Li) form solid bicarbonates `MHCO_(3)`. All alkali metals form nitrates having formula `MNO_(3)`. They are colourless, water SOLUBLE, electrovalent compounds.