Atomic Structure

• Electrons

  Approximately two thousand times smaller than protons or neutrons, negatively charged with a charge of one minus
• Stable isotopes are generally one or two per element, while unstable isotopes decay into other elements by emitting radiation
• Electrons in an atom are arranged in energy levels called shells, with each shell further away from the nucleus and increasing in energy level
• Mass number is the total number of protons and neutrons together in an atom
• Number of protons and electrons in an atom is the same
• Isotopes are atoms with the same number of protons but different numbers of neutrons
• Structure of an atom

  1. Nucleus contains individual protons and neutrons

  2. Electrons orbit around the nucleus in shells
• Protons

  Positively charged particles with a charge of one plus and a relative mass of one
• Ionization occurs when an electron absorbs enough energy to leave the atom, leaving the atom with a positive charge and becoming a positive ion
• Radioactive decay is the process where unstable isotopes decay into other elements by emitting radiation
• Information inside a periodic table box

  • Elemental symbol
  • Atomic number
  • Mass number
• Atomic number is how many protons the atoms of an element have, determining the element
• Ionizing radiation can knock electrons off atoms, ionizing them
• Electrons can jump to higher energy levels if they gain enough energy, becoming excited, and then fall back down, re-emitting energy as electromagnetic radiation
• Neutrons

  Neutral particles with a relative mass of one