Points to Remember: • The valency of an element is the number of electrons donated or accepted by its ‘atom’ during chemical combination. • There are some elements with more than one valency e.g., iron, copper, tin, lead. • Two or more different non-metals that collectively accept or donate one or more electrons and become negatively or positively charged in the process are called radicals. • A chemical reaction involves the transformation of original substance into an altogether new substance(s). • A chemical reaction can be represented with the help of the symbols or the formulae of the elements and the compounds taking part in that reaction. This gives a chemical equation. • Certain necessary conditions for a chemical reaction to happen are — close contact, solution form, heat, light and catalyst. • Characteristics of chem...
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