Question

what do you mean by variable valency​

Answer 1

Answer:

Certain elements combine with other atoms, donating, accepting or sharing electrons in different proportions depending on the nature of the reaction. This is termed variable valency.

Answer 2

Some elements possess more than one valence. Such elements are said to possess variable valency.

→ For example, iron has two electrons in its outermost shell (valence shell). On donating these electrons, its valency becomes 2. However, under specific experimental conditions, it can lose another electron from the shell next to valence shell. In such a case, the ion formed has 3 electropositive valencies.

• outermost shell (valence shell). On donating these electrons, its valency becomes 2. However, under specific experimental conditions, it can lose another electron from the shell next to valence shell. In such a case, the ion formed has 3 electropositive valencies. In short, iron exhibits two valencies 2 and 3. The Latin name of iron is Ferrum. For lower valency, it is written as Ferrous and the symbol is Fe 2+.
• For higher valency, it is written as Ferric and the symbol is Fe 3+.

Hope It Helps ☺️