1.1.4 Atomic Structure, Ions and Isotopes

In this lesson, we will explore the charges carried by the three main subatomic particles found in atoms: protons, neutrons, and electrons. We will also discuss how the numbers of protons and electrons in an atom determine its overall electrical charge and its atomic number.

Relative Electrical Charges of Subatomic Particles

Atoms are composed of three primary subatomic particles: protons, neutrons, and electrons. Each of these particles carries a relative electrical charge, as follows:

• Proton: +1
• Neutron: 0
• Electron: -1

Protons have a positive charge, neutrons have no charge (neutral), and electrons have a negative charge. These charges are relative to each other and allow for the balancing of positive and negative charges within an atom.

The Nuclear Model

The nuclear model describes the structure of an atom. According to this model, the atom consists of a small, dense, and positively charged nucleusA membrane-bound organelle in eukaryotic cells that contains DNA. at the centre. The nucleus contains protons and neutrons, while electrons orbit the nucleus in energy levels or orbitals.

Electrons and Protons in an Atom

In an atom, the number of electrons is equal to the number of protons in the nucleus. Electrons are found in energy levels or orbitals surrounding the nucleus. They contribute to the atom's overall negative charge due to their negative electrical charge. Protons, on the other hand, are located in the nucleus and carry a positive electrical charge. The positive charge of the protons balances the negative charge of the electrons, resulting in an overall neutral charge for the atom.

Atomic Number and Protons

The number of protons in the nucleus of an atom determines its atomic number. The atomic number represents the identity of an element. For example, hydrogen has an atomic number of 1 because it contains one proton, while carbon has an atomic number of 6 because it contains six protons. All atoms of a specific element have the same number of protons. It is the number of protons that distinguishes one element from another.

Variation in Proton Numbers

Atoms of different elements have different numbers of protons. This variation in the number of protons directly influences the properties and behaviour of different elements. For example, oxygen has eight protons, while sodium has 11 protons. The number of protons in an atom determines its chemical behaviour and its position within the periodic table.

Conclusion

In conclusion, subatomic particles within atoms carry relative electrical charges. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. The balance between positive protons and negative electrons results in an overall neutral charge for atoms. The number of protons determines an atom's atomic number, which represents the element's identity. Different elements have different numbers of protons, leading to variations in their properties and positions within the periodic table.