Atomic Structure

Isotopes

  1. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
  2. As a result, isotopes have the same atomic number but different mass numbers.
  3. Examples of isotopes include:
    • Hydrogen: Protium (¹H), Deuterium (²H), Tritium (³H).
    • Carbon: Carbon-12 (¹²C), Carbon-13 (¹³C), Carbon-14 (¹⁴C).
  4. Isotopes exhibit identical chemical properties but different

Quantum Numbers

  1. Quantum numbers describe the state and position of an electron in an atom.
  2. There are four quantum numbers:
    • Principal Quantum Number (n): Indicates the main energy level or shell of the electron.
    • Azimuthal Quantum Number (l): Defines the subshell and shape of the orbital (0 for s, 1 for p, 2 for d, 3 for f).
    • Magnetic Quantum Number (ml): Specifies the orientation of the orbital in space.
    • S

Bohr's Model of the Atom

  1. Proposed by Niels Bohr in 1913.
  2. Based on Rutherford’s model and Planck's quantum theory.
  3. Electrons revolve around the nucleus in fixed circular paths called orbits or energy levels.
  4. These energy levels are represented as n = 1, 2, 3, ... (principal quantum numbers).
  5. Each orbit has a fixed amount of energy, and electrons do not radiate energy while in a stable orbit.
  6. Electrons can transition betwee

Dalton's Atomic Theory

  1. Proposed by John Dalton in 1803.
  2. It was the first scientific theory to describe the nature of matter in terms of atoms.
  3. Matter is made up of small, indivisible particles called atoms.
  4. Atoms of a given element are identical in size, mass, and other properties.
  5. Atoms of different elements differ in size, mass, and other properties.
  6. Atoms cannot be created, divided, or destroyed during chemical reactions.
  7. Atoms combine in simple whole-number ratios to form

Protons

  1. The proton is a positively charged particle with a relative charge of +1.
  2. The atomic number is determined by the number of protons in the nucleus.
  3. Protons were discovered by Ernest Rutherford in 1917.
  4. The charge of a proton is +1.6 × 10⁻¹⁹ coulombs.
  5. Protons are part of the nucleus and contribute to the atom's mass.

Neutrons

  1. The neutron has no charge, making it neutral