Chem

• Element


  A substance that cannot be broken down into simpler substances
• Matter


  Anything that has mass and takes up space
• Chemical change


  A change in matter that occurs when substances combine to form new substances
• Periodic table structure


  • Vertical columns (groups)
  • Horizontal rows (periods)
• Elements are pure substances that cannot be broken down into other substances by physical and chemical means
• Amino acids


  Building blocks for proteins
• NaCl is a compound, C is not a compound
• Chemical reaction


  The process by which chemical bonds are broken and formed
• The element symbol for oxygen is O
• Electron cloud


  The region around the nucleus occupied by the electrons
• An atom has no net electric charge because the positively charged protons cancel out the negatively charged electrons
• The element symbol for iron is Fe
• The three particles that make up an atom are protons, neutrons, and electrons
• Atomic number


  Equal to the number of protons and the number of neutrons
• Mixture


  A combination of sand and salt that can be separated rather easily
• The symbol for the element sulfur is S