Subjects

  • No topics available

← Wood Technology & Design 1-4

Structure of the Atom

Describes subatomic particles, atomic number, mass number, and isotopes.

📘 Topic Summary

The structure of the atom is a fundamental concept in chemistry that describes the composition and organization of atoms, which are the building blocks of matter. Atoms consist of three main parts: protons, neutrons, and electrons, each with its own unique properties and functions. Understanding the structure of the atom is crucial for understanding chemical reactions and the behavior of elements.

📖 Glossary
  • Proton: A positively charged subatomic particle found in the nucleus of an atom.
  • Neutron: A neutral subatomic particle found in the nucleus of an atom.
  • Electron: A negatively charged subatomic particle that orbits the nucleus of an atom.
  • Atomic Number: The number of protons present in the nucleus of an atom, which determines the element's identity.
  • Mass Number: The total number of protons and neutrons present in the nucleus of an atom.
⭐ Key Points
  • Atoms are made up of three main parts: protons, neutrons, and electrons.
  • Protons have a positive charge, while neutrons have no charge.
  • Electrons orbit the nucleus at specific energy levels.
  • The atomic number determines an element's identity.
  • Isotopes are atoms with the same number of protons but different numbers of neutrons.
  • Atoms can gain or lose electrons to form ions.
  • The mass number is the sum of protons and neutrons in an atom.
🔍 Subtopics
Atomic Number

The atomic number of an element is the number of protons present in the nucleus of an atom. It determines the identity of an element and remains constant for all atoms of that element. The atomic number is denoted by the symbol Z and ranges from 1 to 118. For example, hydrogen has an atomic number of 1, while oxygen has an atomic number of 8.

Mass Number

The mass number of an atom is the total number of protons and neutrons present in its nucleus. It is denoted by the symbol A and is equal to the sum of the atomic number (number of protons) and the number of neutrons. The mass number determines the overall mass of an atom.

Protons and Neutrons

Protons are positively charged particles that reside in the nucleus of an atom, along with neutrons which have no charge. Protons determine the atomic number of an element, while neutrons contribute to the mass number. The number of protons remains constant for all atoms of a given element.

Electrons

Electrons are negatively charged particles that orbit the nucleus of an atom. They have very little mass compared to protons and neutrons. The number of electrons in an atom is equal to its atomic number, and each electron has a specific energy level or shell.

Isotopes

Isotopes are atoms of the same element that have different numbers of neutrons. This variation does not affect the chemical properties of the element, but it can affect its physical properties such as mass and density. Isotopes with the same atomic number but different mass numbers are also known as isotopic variants.

Atomic Structure

The atomic structure consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels or shells. The number of electrons in each shell is determined by the atomic number and follows specific rules such as the Aufbau principle and Hund's rule.

Chemical Reactions

Chemical reactions involve the interaction between atoms, molecules, or ions to form new substances. Chemical bonds are formed when electrons are transferred or shared between atoms, resulting in the creation of compounds with unique properties.

Atomic Properties

The atomic properties of an element include its chemical reactivity, physical state, and ability to form compounds with other elements. The atomic number and mass number determine the properties of an atom, which in turn influence the properties of the substances it forms.

🧠 Practice Questions

  1. What is the charge of a proton?

  2. Which part of an atom determines its identity?

  3. What is the charge of an electron?

  4. What is the sum of protons and neutrons in an atom called?

  5. Which part of an atom can gain or lose electrons to form ions?

  6. What is the atomic number of hydrogen?

  7. How many protons are in the nucleus of an atom with an atomic number of 8?

  8. What is the mass number of an atom with 6 protons and 6 neutrons?

  9. Which type of particles have no charge?

  10. What is the term for atoms with the same number of protons but different numbers of neutrons?

  1. What is the atomic structure composed of? (2 marks)

  2. How do isotopes differ from each other? (2 marks)

  3. What determines the chemical reactivity of an element? (2 marks)

  4. How do electrons orbit the nucleus of an atom? (2 marks)

  5. What is the significance of the atomic number in determining the identity of an element? (2 marks)

  1. Describe the structure of an atom and its components. (20 marks)

  2. Explain how the atomic number and mass number determine the properties of an element. (20 marks)