How do the following properties change in group - 1 and in the third period? Explain with example.
(d) Nature of oxides.

Explanation

Nature of oxides of elements: All IA group elements are alkali metals. Their oxides are basic in nature. They dissolve in waterto give basic solutions which changes red litmus blue. E.g `Na_(2) O, CaO, MgO` etc
`Na_(2) O + H_(2)O rarr 2NaOH`
`CaO + H_(2)O rarr Ca(OH)_(2)`
`MgO + H_(2) O rarr Mg(OH)_(2)`
The basic nature of these oxides increases from top to bottom in the group. In a period basic properties decreases and acidic properties increases.