Understanding Elements

Elements are substances that consist of just one type of atom.
Each element is represented by a unique chemical symbol, typically one or two letters e.g., H for Hydrogen, O for Oxygen, Mg for Magnesium.
Elements can be metallic (metals), non-metallic (non-metals), or metalloids (possess properties of both metals and non-metals).

Arrangement in Periodic Table

The periodic table organises elements based on their atomic number and chemical properties.
Element’s position in the periodic table determines its group number (vertical columns) and period number (horizontal rows).
Elements in the same group usually have similar chemical properties because they have the same number of electrons in their outer shell.
Metallic elements are on the left side of the periodic table, while non-metallic elements are on the right.

Atoms of an element consist of a nucleus, containing protons and neutrons, with electrons orbiting around the nucleus.
Protons are positively charged, electrons are negatively charged and neutrons have no charge.
The number of protons in an atom gives the atomic number of the element, and the sum of protons and neutrons gives the mass number.

Chemical properties of an element describe its behaviour in chemical reactions, including reactivity and valency.
Physical properties include melting and boiling point, density, and conductivity of heat and electricity.
Within a group in the periodic table, the reactivity of metals increases down the group while the reactivity of non-metals decreases down the group.

Isotopes are atoms of the same element that have different numbers of neutrons and consequently, different mass numbers.
Isotopes of an element have identical chemical properties but can differ in physical properties such as density and rate of diffusion.

Elemental analysis can be conducted using techniques such as spectroscopy, mass spectrometry, and chemical tests.
These techniques can determine the identity of an element, its concentration, or its atomic structure.