Structure of the Atom

Atoms are the basic building blocks of matter, they are composed of:

Particles in the Atom

Protons: They are positively charged and lie in the nucleus of the atom.
Neutrons: They are neutral, i.e., have no charge and also lie in the nucleus of the atom.
Electrons: They are negatively charged and orbit the atom’s nucleus.

Atomic Number and Atomic Mass

Atomic number: It denotes the number of protons present in an atom.
Atomic mass: It’s the combined number of protons and neutrons.

Characteristics of Atomic Particles

Protons and neutrons are heavy, and have approximately the same mass, much heavier than the mass of electrons.
Electrons move around the nucleus in specific energy levels or shells.

Configurations of Electrons

Electrons occupy energy levels around an atom’s nucleus.
The lowest energy level is closest to the nucleus, and can hold up to 2 electrons.
The next energy level can contain up to 8 electrons, and so on.

Isotopes

Elements might have atoms with different numbers of neutrons. These are called isotopes.
All isotopes of a particular element have the same number of protons but vary in the number of neutrons.
Isotopes of an element have almost similar chemical properties because they have the same number of electrons.

Ions

When an atom loses or gains an electron, it becomes an ion.
Metals tend to lose electrons to become positive ions, while non-metals tend to gain electrons to become negative ions.

Remember, understanding the structure of the atom is essential as it forms the foundation for understanding the chemical behaviour of elements and the nature of chemical reactions.