Periodic table

• Atom


  Small particles everything is made of
• Molecule


  More than one atom bonded together
• Element


  Made of a single type of atom
• Compound


  Two or more atoms chemically bonded
• Mixture


  A group of molecules or atoms not joined by chemical bonds and easily separated
• Exothermic reaction


  A reaction that transfers energy from the surroundings
• Endothermic Reaction


  A reaction that absorbs energy from the surroundings
• Diatomic


  A molecule made of two atoms
• Reactant


  Substance that react together
• Physical Properties

  • Color
  • Odor
  • Density
  • Melting point
  • Boiling point
  • Solubility
  • Conductivity (electrical and thermal)
  • Magnetism
  • Hardness
  • Viscosity (thickness or resistance to flow)
  • Flexibility
  • State of matter (solid, liquid, gas)
  • Texture
  • Luster (shininess)
  • Refractive index
• Chemical Properties


  • Flammability (ability to burn)
  • Reactivity (ability to undergo chemical reactions)
  • Stability (resistance to change or decomposition)
  • Toxicity
  • Corrosiveness (ability to corrode or degrade other substances)
  • Oxidation state
  • pH (acidity or basicity)
  • Combustibility (ability to combust or catch fire)
  • Sensitivity to light or heat
  • Decomposition temperature
• Physical Changes


  • Melting of ice
  • Boiling of water
  • Dissolving salt in water
  • Crushing a can
  • Cutting paper
  • Changes in state of matter (solid to liquid, liquid to gas)
  • Mixing sand and water
  • Bending a wire
• Chemical Changes


  • Burning of wood
  • Rusting of iron
  • Digestion of food
  • Fermentation of grapes into wine
  • Cooking an egg
  • Photosynthesis in plants
  • Electrolysis of water
  • Decomposition of organic matter
• All matter is made up of atoms
• The atoms in an element are all identical
• Atoms are indestructible and cannot be created or destroyed
• In compounds each atom of an element is always joined to a fixed number of atoms
• During chemical reactions atoms rearrange to make substances and there is no change in mass
• Alkali Metals


  • Less dense than other metals
  • One loosely bound valence electron
  • Highly reactive, with reactivity increasing moving down the group
  • The largest atomic radius of elements in their period
  • Low ionization energy
  • Low electronegativity
• Alkaline Earth Metals


  • Two electrons in the valence shell
  • Readily form divalent cations
  • Low electron affinity
  • Low electronegativity
• The lanthanides (rare earth) and actinides are also transition metals
• The basic metals are similar to transition metals but tend to be softer and to hint at nonmetallic properties
• In their pure state, all of these elements tend to have a shiny, metallic appearance
• While there are radioisotopes of other elements, all of the actinides are radioactive
• Transition Metals


  • Very hard, usually shiny, ductile, and malleable
  • High melting and boiling points
  • High thermal and electrical conductivity
  • Form cations (positive oxidation states)
  • Tend to exhibit more than one oxidation state
• Nonmetals


  • High ionization energy
  • High electronegativity
  • Poor electrical and thermal conductors
  • Form brittle solids
  • Little if any metallic luster
  • Readily gain electrons
• The halogens and noble gases are nonmetals, although they have their own groups, too
• Halogens


  • Extremely high electronegativity
  • Very reactive
  • Seven valence electrons, so elements from this group typically exhibit a -1 oxidation state
• Noble Gases


  • Have complete valence electron shells, so they act differently
  • Unreactive
  • Very low electronegativity or electron affinity