What are Subatomic Particles?
The name "atom" is derived from the Greek word "a-tomio," which means "uncuttable" or "non-divisible." For the longest period, scientists assumed that atoms were indestructible.
However, some scientists discovered in the early twentieth century that atoms may be broken down further into smaller components such as electrons, protons, and neutrons. Subatomic particles are what they're called.
Discovery
The rules of conservation of mass, constant composition, and various proportions were all satisfactorily explained by Dalton's atomic theory.
However, it was unable to account for certain other facts, such as the creation of electricity on rubbing glass or ebonite when silk or fur was used.
These findings paved the way for the discovery of subatomic particles in the twentieth century. Let's take a look at how the three subatomic particles were discovered.
Discovery of Electron
Electrons are subatomic particles. It spins around an atom's nucleus. When electrons are lost or gained from an atom, ions are created. Chemical bonding occurs when electrons from different atoms join together. A few points about the discovery of electrons and their properties are listed below:
J. Thompson is credited with discovering electrons since he was the first to precisely calculate an electron's mass and charge.
All elements have an equal number of electrons and protons in their atoms.
When compared to the mass of a proton, the mass of an electron is insignificant. Its mass is discovered to be 1/1837 times that of a proton.
An electron has a charge of -1.602 * 10-19 Coulombs.
Electrons are negatively charged subatomic particles.
Discovery of Proton
Positively charged particles, sometimes known as canal rays, were discovered as a result of the cathode ray tube experiment. The following are their characteristics:
They are dependent on the type of gas in the cathode ray tube, unlike cathode rays. The positively charged gaseous ions are these.
The charge-to-mass ratio of these particles varies depending on the gas they come from.
A multiple of the fundamental unit of electrical charge is carried by some positively charged particles.
In an electrical or magnetic environment, these particles behave in the opposite way as cathode rays.
In 1919, this was characterised and the lightest and smallest positively charged particle made from hydrogen came into existence known as Proton.
Discovery of Neutron
Later on, scientists found an electrically neutral atom component. Chadwick, a scientist, did an experiment in which he bombarded a thin sheet of beryllium with particles in 1932. He saw the emission of electrically neutral particles that were slightly heavier than protons. As a result, these particles were given the name neutrons.
FAQs on Subatomic Particles
1. What exactly is a subatomic particle?
A subatomic particle is any particle that is smaller than an atom. Atoms, which are the basic building blocks of all matter, are themselves composed of these even smaller particles. The three primary subatomic particles that make up an atom are protons, neutrons, and electrons.
2. What are the main differences between protons, neutrons, and electrons?
The three main subatomic particles differ in their charge, mass, and location within the atom. Here’s a quick summary:
- Protons: Have a positive (+) electrical charge and are found in the atom's central core, called the nucleus.
- Neutrons: Have no charge (neutral) and are also located in the nucleus along with protons.
- Electrons: Have a negative (-) electrical charge and orbit the nucleus in specific energy levels or shells. They are much lighter than protons and neutrons.
3. How do subatomic particles determine an element's identity and properties?
The number of subatomic particles defines an element's characteristics. The number of protons determines the atomic number and identifies the element (e.g., any atom with 6 protons is Carbon). The total number of protons and neutrons gives the atom its mass number. The number of electrons determines the atom's overall charge and how it will react chemically with other atoms.
4. What happens to an atom if you change the number of its subatomic particles?
Changing the number of subatomic particles fundamentally alters the atom:
- Changing Protons: The atom transforms into a completely different element. For example, if a Helium atom (2 protons) gains a proton, it becomes a Lithium atom (3 protons).
- Changing Neutrons: The atom becomes an isotope of the same element. It has the same chemical properties but a different mass.
- Changing Electrons: The atom becomes an ion. If it loses electrons, it becomes a positively charged cation. If it gains electrons, it becomes a negatively charged anion.
5. How do the charges of subatomic particles keep an atom together?
The stability of an atom is a result of the balance between electrical forces. The positively charged protons in the nucleus create a strong force of attraction that pulls the negatively charged electrons towards it, keeping them in orbit. This is similar to how opposite poles of a magnet attract each other. Neutrons help by adding mass and a strong nuclear force that overcomes the repulsion between the positively charged protons packed together in the nucleus.
6. Are there any real-world uses for subatomic particles?
Yes, subatomic particles have many important applications. For instance, beams of protons are used in a medical treatment called proton therapy to target and destroy cancer cells with high precision. Beams of electrons are used in electron microscopes to see extremely small objects and were also used to create images on older CRT television and computer screens.
7. Are protons and neutrons the smallest particles that exist?
While protons and neutrons are fundamental to an atom's structure, they are not the smallest particles. According to the Standard Model of particle physics, protons and neutrons are composite particles made up of even smaller elementary particles called quarks. Electrons, however, are considered elementary particles, meaning they are not made of anything smaller.
8. If neutrons have no charge, why are they so important inside an atom's nucleus?
Neutrons are crucial for nuclear stability, especially in atoms with many protons. The protons in a nucleus are all positively charged and naturally repel each other. Neutrons act like a 'buffer' or 'glue' by contributing to the strong nuclear force, which is a powerful attractive force that holds the nucleus together. Without enough neutrons, the repulsive forces between protons would cause the nucleus to break apart.
