Each and everything that exists in this world consists of atoms. They are the smallest particles that make up an element. The word atom has been derived from a Greek word atomos that means uncuttable. These particles are named so because they are undividable and described as the basic unit of matter.
The particles that are smaller than atom are known as subatomic particles. All four states of matter, solid, liquid, gas and plasma are composed of atoms. The particles that make up an atom are electrons, protons, and neutrons.
Quick Facts: –
- Protons have a positive electrical charge, electrons have a negative electrical charge and neutrons have no charge at all.
- The mass of a proton is essentially the same as that of a neutron, but 1,840 times greater than the mass of an electron.
- Electrons are grouped in layers called shells.
- The most abundant type of atom in the universe is the hydrogen atom.
- Atoms are classified according to their number of protons or neutrons.
- In 1661, Robert Boyle was the first scientist to publish the theory that all matter is composed of atoms.
- An atom is mostly empty space. Its nucleus is extremely dense contains almost all the mass.
- They are so tiny that you cannot see them even with the most powerful microscope.
- There are more than 100 different types of these particles. 92 of them occur naturally while remaining ones are made in labs.
- Molecules are formed when two or more atoms are combined together.
- The simplest molecules consist of just two atoms and are shaped like dumbbells.
