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AZXC Notation Overview

Sep 3, 2025

Overview

This lecture introduces AZXC notation as a method to represent atomic structure, including protons, neutrons, electrons, and charge, for any element.

AZXC Notation Structure

  • AZXC notation is used to identify the number of protons, neutrons, electrons, and charge for an atom.
  • The format is: X (atomic symbol), Z (atomic number, lower left), A (mass number, upper left), C (charge, upper right).
  • X is a one- or two-letter symbol from the periodic table, unique for each element (e.g., C for carbon, N for nitrogen).

Symbols and Their Meanings

  • Z (lower left) is the atomic number, representing the number of protons.
  • The atomic number (Z) is unique to each element and determines the element’s identity.
  • A (upper left) is the mass number, equal to the sum of protons and neutrons (A = protons + neutrons).
  • The mass number (A) is not listed on the periodic table and can vary for isotopes of an element.
  • C (upper right) is the charge, found by subtracting the number of electrons from protons (C = protons - electrons).

Using AZXC Notation

  • To determine neutrons: neutrons = A - Z.
  • To determine charge: charge (C) = number of protons (Z) - number of electrons.
  • Neutral atoms have equal numbers of protons and electrons, resulting in a charge of zero.

Key Terms & Definitions

  • Atomic Symbol (X) — One- or two-letter abbreviation for an element (e.g., C for carbon).
  • Atomic Number (Z) — Number of protons in the atom; identifies the element.
  • Mass Number (A) — Total of protons and neutrons in the nucleus.
  • Charge (C) — Difference between the number of protons and electrons (C = protons - electrons).

Action Items / Next Steps

  • Practice identifying protons, neutrons, electrons, and charge using AZXC notation for various elements.
  • Prepare to solve problems where some atomic information is missing and must be found using AZXC notation.