Atomic structure

• Proton


  Positively charged particle found in the nucleus of an atom
• Neutron


  Particle found in the nucleus with no charge
• Electron


  Negatively charged particle orbiting the nucleus
• Atomic Number


  The number of protons in an atom's nucleus, unique to each element
• Nucleus


  Central part of an atom containing protons and neutrons
• Atom


  The smallest unit of matter that retains the properties of an element
• Element


  A pure substance consisting of only one type of atom
• Nucleus


  • The central part of an atom containing protons and neutrons
• Proton


  • Positively charged particle in the nucleus
• Neutron


  • Neutral particle in the nucleus
• Electron


  • Negatively charged particle orbiting the nucleus in electron shells
• Atomic Number (Z)


  Number of protons in an atom (defines the element)
• Mass Number (A)


  Sum of protons and neutrons in the nucleus
• Electron Shells


  • Regions around the nucleus where electrons are found
  • 1st shell: up to 2 electrons
  • 2nd shell: up to 8 electrons
  • 3rd shell: up to 18 electrons
• Valence Electrons


  Electrons in the outermost shell, important for chemical bonding
• Isotopes


  Atoms of the same element with different numbers of neutrons (same atomic number, different mass number)
• Groups


  • Columns in the periodic table; elements in the same group have similar properties
• Periods


  • Rows in the periodic table; properties change progressively across a period
• Ionic Bond


  Transfer of electrons from one atom to another, resulting in charged ions
• Covalent Bond


  Sharing of electrons between atoms
• Protons = Atomic Number
• Neutrons = Mass Number - Atomic Number
• Electrons in a neutral atom = Protons
• Use the periodic table to determine the number of valence electrons