Atoms, Elements, Compounds

• What is an atom?

  Smallest part of an element that can exist
• What is an element?


  A substance that contains only one type of atom
• What is a compound?

  a substance that contains two or more elements chemically bonded together
• What are atoms made up of?

  Protons, neutrons, and electrons
• What is the radius of an atom?

  0.1 nanometers (1x10-10m)
• What is the radius of an atomic nucleus?

  1 x 10-14
• Which subatomic particle determines which element an atom is?

  Proton
• which subatomic particles have the same mass as each other?

  Protons and neutrons
• What is the mass number of an atom?

  total number of protons and neutrons in its nucleus
• What is the atomic number in an atom?

  Number of protons
• How do you work out neutrons in an atom?

  Subtract the atomic number from the atomic mass.
• In chemical reactions, what do compounds separate back into?

  Elements
• Formula for carbon dioxide 


  CO2
• Formula for water 


  H2O
• Formula for oxygen

  O2
• Formula for hydrogen 


  H2
• Formula for nitrogen 


  N2
• Formula for ammonia 


  NH3
• Formula for hydrochloric acid 


  HCl
• Formula for sulfuric acid 


  H2SO4