What are Atoms made of?

An atom is composed of three particles, namely,  neutrons, protons and electrons with hydrogen as an exception without neutrons.

• Every atom has a nucleus that bounds one or more electrons around it.
• The nucleus has typically a similar number of protons and neutrons which are together known as nucleons.
• The protons are positively charged, electrons are negatively charged and neutrons are neutral.

What is Atomic Mass?

It is the mass of an atom in a chemical element. It is roughly equivalent to the total neutrons and protons present in the atom. It is expressed in atomic mass units (denoted by u). 1amu is equal to the exactly one-twelfth of the mass of 1 atom of C-12 and the relative atomic masses of elements is determined with respect to-12 atom.

Atomic masses of Some Elements

Salient features of Dalton’s Atomic Theory

• The matter is composed of minute particles known as atoms.
• Atoms are indivisible particles that can’t be destroyed or created through chemical reactions.
• All atoms of an element have identical chemical properties and mass whereas, atoms of different elements have different chemical properties and masses.
• Atoms combine in a ratio of small whole numbers to form compounds.

The matter is anything and everything in our surrounding. It has basic structural and fundamental units. Let us examine the concept of matter with an example. Taking a storybook into consideration and dividing its structure. The book contains many pages, each page consists of paragraphs, and each paragraph has many sentences.

Each sentence will further have many words and each word will have characters. Therefore we have divided a storybook into characters. This is exactly the same case when we take the matter into account. The matter is made up of substances which contain molecules. The molecules, in turn, are made up of groups of atoms.

Atoms in simple terms are defined as the smallest unit of matter. In ancient times scientists wondered whether the matter could be further divided or not. Around 500 BC the idea of divisibility of matter evolved in India. A scientist named Maharishi Kanad stated that matter can be divided into smaller and smaller units. The smallest unit of matter after which further division was not possible was known as parmanu.