Question

How to write chemical formula in criss cross method

Answer 1

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Writing in Criss Cross Method

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RULE 1

[a] write the correct symbols of two elements.Ex : Aluminium & Oxygen Al O[b] above each symbol, write the correct valenceAl3+ O2-[c] Criss-cross the valence and drop the algebraic sign.Al2O3

RULE 2

When the subscript is number 1, subscript is not

When the subscript is number 1, subscript is notwritten. Ex. Sodium Chloride - Na1+ Cl1- --- NaCl

RULE 4

When there are multiple numbers of an individual polyatomic ion , parentheses must be used to separate the polyatomic ion from the subscirpt.

Ex. Ammonium Sulphate- - NH41+ SO42-....... (NH4)2 SO4

Answer 2

Explanation:

refer to the attachment