What is an Atom?
Definition of an Atom:
An atom is the smallest unit of an element that retains the chemical properties of that element. It consists of a nucleus (containing protons and neutrons) and electrons revolving around it.
Symbols of Elements (IUPAC System)
Elements are represented by symbols as per the IUPAC system.
The first letter of the symbol is always capital, and the second letter (if present) is lowercase.
Examples:
Hydrogen (H)
Oxygen (O)
Calcium (Ca)
Iron (Fe)