Atomic Number and the Periodic Table

The Periodic Table is developed to systematically arrange elements based on their atomic number.
An atomic number is an important feature that identifies and distinguishes elements. It refers to the number of protons in the nucleus of the atom.
The atomic number also defines the order in which elements are arranged in the Periodic Table. It starts from Hydrogen with an atomic number of 1 and continues in ascending order.
Elements in the same vertical column of the Periodic Table, known as a group, share similar chemical properties. This is because they have the same number of electrons in their outer shell.
Elements in the same horizontal row of the Periodic Table, known as a period, have the same number of electron shells or energy levels.
Elements with an increased atomic number have a tendency to have an increased atomic radius due to the addition of more electron shells.
The greater the atomic number of an element, the greater the mass of its atom. This is because as protons and neutrons are added to the nucleus, the mass of the atom increases.
Elements in the Periodic Table are classified into metals, non-metals, and metalloids based on their atomic numbers and physical properties.
The atomic number is essential for understanding the periodic properties of elements like the atomic radius, ionisation energy, electronegativity, and electron affinity. These properties vary in a predictable way across the Periodic Table.
The number of electrons in an atom is usually equal to the atomic number, making it electrically neutral. However, when the number of electrons changes (during ion formation for example), the atom gets an electric charge.
The knowledge of atomic numbers and how they are depicted on the Periodic Table can aid in identifying and understanding the behaviour of different elements and their compounds.