Atomic Physics Lecture 1: Atomic Structure

Atomic Composition

• An atom consists of a central nucleus containing protons and neutrons, and smaller particles orbiting the central nucleus known as electrons.
• The number of electrons orbiting a nucleus equals the number of protons in the nucleus, and when an atom or molecule gains or loses electrons, it becomes an ion.
• Ions can be positively or negatively charged, depending on whether electrons are removed or gained.

The Atom

• An atom is the smallest particle into which an element can be divided without losing its chemical properties.
• An atom is composed of the atomic nucleus and electrons.

The Atomic Nucleus

• The atomic nucleus is composed of protons and neutrons, which are collectively known as nucleons.
• The positive charge of the protons equals the negative charge of the electrons, resulting in a neutral total electric charge of the atom.
• Protons have a positive charge, while neutrons have no electric charge.

Atomic Number (Z)

• The atomic number is the number of protons present in the atomic nucleus.
• The atomic number characterizes a chemical element and determines its position on the periodic table.
• The atomic number is equal to the number of electrons in a neutral atom.

Mass Number (A)

• The mass number is the total number of nucleons (protons plus neutrons) in the atomic nucleus.
• The mass number can be calculated as A = Z + N, where N is the number of neutrons.

Mass Defect

• The mass defect is the difference between the sum of the masses of all nucleons in the nucleus and the nuclear mass.
• The mass defect can be represented by the equation: Δm = Mp + Mn - M(A,Z).
• 1 amu (atomic mass unit) is equal to 931.49 MeV or 1.49239 x 10^(-10) J.

Nuclear Binding Energy

• Nuclear binding energy is the energy required to separate an atomic nucleus completely into its constituent protons and neutrons.
• Nuclear binding energy can be represented by the equation: B.E = [Zmp + NmN - M(A,Z)]c^2.
• Nuclear binding energy can be calculated using the mass defect and the atomic mass unit.

This quiz covers the basic composition of an atom, including the nucleus, protons, neutrons, and electrons. Learn about the structure of atoms and their components.