Chemistry PERIODICITY IN PROPERTIES OF OXIDES & OXYACIDS

Nature of Oxides :

If difference of the two electronegativities (`X_O - X_A`) is `2.3` or more then oxide will be basic in nature. Similarly if value of `X_O - X_A` is lower than `2.3` then the compound will be first amphoteric then acidic in nature. See Table.

`text(Basic character of oxides)` `prop` `text(Difference of electronegativities of metal and oxide)`. Therefore basic character decreases in the period and acidic character increases.

`text(Nature of Oxides)`

`ast` Oxides of general metals are basic in nature whereas oxides of nonmetals are acidic in nature.

`ast` Basic nature of oxides `prop` Metallic nature.

`ast` Basic nature of oxides `prop` Electropositive nature.

`ast` Basic nature of oxide `prop` `1/(text(number of electrons in the outermost shell))`.

`ast` Acidic nature of oxides `prop` Non-metallic nature.

`ast` Acidic nature of oxides `prop` Electronegative nature.

`ast` Acidic nature of oxides `prop` number of electrons in outermost shell.


Nature of Oxyacids :

- Those inorganic acids in which `X-OH` group is present are called oxy acids. (Here `X`= a non metal) like `HOCl` is an oxyacid.

`text(In a Period :)`

- Moving from left to right in a period strength of oxy acids increases like Order of strength of oxyacid of elements of second period
`H_3BO_3 < H_2CO_3 < HNO_3`

- Order of strength of oxy acids of elements of third period `H_2SiO_3 < H_2SO_4 < HClO_4`

`text(In a Group :)`

- Moving upwards to downward in a group, strength of oxy acids decreases Like - In `VA`- `HNO_3 > H_3PO_4`. When amount of oxygen increases in an oxyacid of an element (i.e. on increasing oxidation state of element) strength of acid increases like

(a) `H_2SO_3 < H_2SO_4`

(b) `HClO < HClO_2 < HClO_3 < HClO_4`

Stability of acids also increases in the same order.

 
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