What are the types properties and charges of subatomic particles in an atom
The history of the atom begins with a Greek philosopher named Democritus around 450 B.C. He wondered what would happen if we cut a piece of matter, such as chalk, into smaller and smaller pieces. He thought that a point would be reached where matter could not be cut into further small pieces.
He called those pieces ‘atomos’. In the year around 1800, a British chemist named John Dalton revived Democritus’s early ideas about the atom. He did many experiments that provided evidence for atoms.
He researched the properties of compounds. He showed that a compound always consists of the same elements in the same ratio.
He also comes with Dalton's Atomic Theory. One of his theories states that All substances are made of atoms, and they are the smallest particles of matter. They cannot be further subdivided into smaller particles. However, in the early 20th century, some scientists like J.J Thomson, Rutherford, etc, showed that atoms can be further subdivided into smaller parts, and the three subatomic particles of an atom are proton, electron, and neutron.
3 Subatomic Particles of an Atom
The number of subatomic particles in an atom is three which includes Proton, Neutron, and Electron. Each of them is discussed below.
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Proton Subatomic Particle
Protons and Neutrons together make the nucleus of an atom and are also called nucleons. Proton was first discovered by Ernest Rutherford in the year 1919 when he was performing his gold foil experiment. He projected alpha particles (called helium nuclei) at gold foil, and the positive alpha particles were deflected. From that, he concluded that a proton exists in a nucleus and protons are the subatomic particles that are positively charged. The atomic number of an atom is the number of protons present in an atom. The mass of a proton is 1.676 x 10-24 gramsand the charge is 1.602 x 10-19 Coulombs.
Electrons
Electron was discovered by John Thomson in the year 1897. They are the negatively charged subatomic particles that revolve around the nucleus of an atom and are located in an electron cloud, which is the area surrounding the nucleus of the atom. The electrons can be removed or gained by an atom to form an ion. These positive and negative charged ions come together to participate in chemical bonding.
The mass of an electron is negligible as compared to the mass of a proton. It is found to have a mass equal to (1/1837) times the mass of a proton. The charge of an electron is 1.602 x 10-19 Coulombs. The 3 subatomic particles of an atom also include Neutron.
Neutron
Neutron was discovered by James Chadwick in the year 1932, They are located in the nucleus with the protons. Neutron along with protons make up the nucleons. They do not carry any charge like proton or electron. The neutron determines the isotope of an atom and its stability. The number of neutrons in an atom is not necessarily equal to the number of protons. The mass of a neutron is 1.676 x 10-24 grams and it is electrically neutral.
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Did You Know?
The Greek philosopher Aristotle, who lived about 100 years after Democritus, rejected Democritus’s idea of atoms. In fact, He thought the idea of atoms was ridiculous and ideas were accepted for more than 2000 years. After that, Dalton’s theory of Atom come into existence.
FAQs on Subatomic Particles of an Atom Structure and Properties
1. What are the subatomic particles of an atom?
The subatomic particles of an atom are protons, neutrons, and electrons. These particles determine the atom’s structure and chemical behavior.
- Protons: Positively charged particles located in the nucleus.
- Neutrons: Neutral particles also found in the nucleus.
- Electrons: Negatively charged particles that move around the nucleus in energy levels or shells.
2. What is the charge and mass of protons, neutrons, and electrons?
The charge and relative mass of subatomic particles differ significantly and define atomic properties.
- Proton: Charge = +1, Relative mass ≈ 1 amu (1.67 × 10-27 kg)
- Neutron: Charge = 0, Relative mass ≈ 1 amu (1.675 × 10-27 kg)
- Electron: Charge = −1, Relative mass ≈ 1/1836 amu (9.11 × 10-31 kg)
3. Where are subatomic particles located in an atom?
In an atom, protons and neutrons are located in the nucleus, while electrons are found in shells or orbitals around the nucleus.
- The nucleus is the small, dense, positively charged center of the atom.
- Electrons occupy discrete energy levels (K, L, M shells or quantum orbitals).
4. What is the difference between protons, neutrons, and electrons?
The main difference between protons, neutrons, and electrons is their charge, mass, and position in the atom.
- Protons: +1 charge, located in nucleus, determine atomic number.
- Neutrons: 0 charge, located in nucleus, determine isotopes.
- Electrons: −1 charge, move around nucleus, determine chemical properties.
5. How do you calculate the number of protons, neutrons, and electrons in an atom?
You calculate subatomic particles using the atomic number (Z) and mass number (A) of an element.
- Protons = Atomic number (Z)
- Electrons (neutral atom) = Atomic number (Z)
- Neutrons = Mass number (A) − Atomic number (Z)
- Protons = 11
- Electrons = 11
- Neutrons = 23 − 11 = 12
6. What is the atomic number and how is it related to subatomic particles?
The atomic number (Z) is the number of protons present in the nucleus of an atom.
- It uniquely identifies an element.
- In a neutral atom, number of electrons = protons.
7. What are isotopes and how are they related to neutrons?
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
- They have the same atomic number (Z).
- They have different mass numbers (A).
- 1H (protium): 1 proton, 0 neutrons
- 2H (deuterium): 1 proton, 1 neutron
- 3H (tritium): 1 proton, 2 neutrons
8. What are ions and how do electrons form ions?
An ion is a charged atom formed when it gains or loses electrons.
- Cation: Formed by loss of electrons (positive charge), e.g., Na → Na+ + e-
- Anion: Formed by gain of electrons (negative charge), e.g., Cl + e- → Cl-
9. Why are electrons important in chemical reactions?
Electrons are important in chemical reactions because chemical bonding involves the transfer or sharing of electrons.
- In ionic bonding, electrons are transferred (e.g., Na+ and Cl- form NaCl).
- In covalent bonding, electrons are shared (e.g., H2 forms by sharing electrons).
10. Who discovered the subatomic particles of the atom?
The three main subatomic particles were discovered by different scientists through key experiments.
- Electron: Discovered by J.J. Thomson (1897) using the cathode ray tube experiment.
- Proton: Identified by Ernest Rutherford (1917) in gold foil and nuclear experiments.
- Neutron: Discovered by James Chadwick (1932) through nuclear bombardment experiments.
