# Valency and writing chemical formulas

> Valency is an element's combining capacity; formulas are written by balancing valencies (e.g. Al2O3, FeCl3), including common groups like SO4 and CO3.

> [ar-EG] الـ valency هي قدرة العنصر إنه يتحد مع غيره؛ والـ formulas بنكتبها عن طريق إننا نوازن الـ valencies (زي Al2O3 و FeCl3)، ومعاها الـ groups الشائعة زي SO4 و CO3.

Part of: Transition Elements (https://yaani.ai/en/learn/chemistry/chem-s3-en.ch1)

## Builds on

- Elements and their symbols
- The four arithmetic operations


Source: https://yaani.ai/en/concept/chem.valency-formulas