13 May

Atoms and Molecules

The name atom comes from the Greek word ‘atomos’ and it means ‘indivisible’. Atom is the smallest unit having the characteristics of a chemical element. Everything surrounding us is made up of atoms. Every living and non living thing around us is made of matter but the building blocks of matter are atoms. The concept of atoms was put forward by Greek philosophers John Dalton and Democritus.

An atom is a small particle comprising of any type of matter such as an element, compounds or a mixture of both. Atoms consist of two regions:the center that has the nucleus, positively charged protons and neutrons. Neutrons are uncharged particles. The outer circlecomprises of electrons that are negatively charged. Atoms are invisible to the eye and are known as basic building blocks. An example is that the elements of gold cannot be broken down or seen and every atom consists of the properties of gold.

Molecules are two or more atoms that are chemically bonded together. Atoms having similar or different elements combine to form molecules. The number of atoms that make up a molecule is termed as atomicity. For example, O2 is formed by combining molecules of two atoms of Oxygen. But when 3 atoms of oxygen are combined an O3 (Ozone) molecule is formed. The prime difference between atoms and molecules is that when atoms of the same proportion combine in different numbers, molecules of different properties can be formulated. But when similar molecules come together in varying numbers, a simple product is formed.

Atoms and molecules persist in all living things and objects. The thickness and form of every object are different due to the varying levels of composition and density. Being very loosely packed molecules can move around easily in gases without colliding. Whereas in liquids, for the particles to remain together, the packing is more compact. In solids, the packing is very compact and barely any movement is permitted within molecules giving the object a shape.

The concept of atoms and molecules is one of the basic chapters of chemistry. Chemistry tuition at primary school enable students to gain a better understanding of the concept and gain further knowledge on the subject.

In Miracle Learning Centre, critical concepts of O Level Chemistry, A Level Chemistry and JC Level Chemistry are broken up into easy digestible lessons and are taught to the students by the best chemistry teachers of Singapore.