Notice the sub-atomic particles in this beryllium atom  It has 4 (blue) protons (So the atomic number is four)  It also has 5 (green) neutrons and 4 (orange) electrons Legend =protons =neutrons =electrons SPI Atoms Notes  We once thought atoms were the smallest particles.  We now know there are even smaller particles  They are called sub-atomic particles Science 4 Be Beryllium 9.0 (protons, neutrons, and electrons)

Atoms are made of three sub-atomic particles… …3 protons (the blue circles) (atomic number is 3) …4 neutrons (the green circles) …3 electrons (the orange circles) Here is a model of a lithium atom SPI Atoms Notes Science 3 Li Lithium 6.9

Protons: positive charge, found in the nucleus of atoms Note: In atoms the number of protons & electrons are the same Neutrons: no charge, also found in the nucleus of atoms SPI Atoms Notes Science Nucleus Legend =protons =neutrons =electrons

 Electrons are located in the electron cloud in areas called electron shells  This atom has 2 electron shells. Nucleus 2nd Shell 1 st Shell The green area is the electron cloud area Nucleus (see cloud in green area below) These can also be called electron energy levels or electron orbitals. SPI Atoms Notes Science Legend =protons =neutrons =electrons

Chemical Changes  Occur when 2 or more substances, due to a chemical reaction, form a compound & change into a new substance.  Compounds are formed when you combine 2 or more or more different reactive elements  Atomic bonds break apart and new atomic bonds are formed  Valence Electrons are transferred or shared  (F.Y.I. This is called ionic & covalent bonding) ….so in other words  chemical changes, chemical bonding and chemical reactions are all connected  Chemical bonding occurs during a chemical reaction resulting in a chemical change SPI Chemical Change Outcomes Notes Science

Compounds  Compounds are formed from chemical reactions Example: When two hydrogen atoms react with one oxygen atom you produce (form) the compound called water (H 2 O). H Oxygen H H H SPI Chemical Change Outcomes Notes Science Memory Trick C = C (chemical reactions = compounds)

5 Key Points About All Chemical Reactions: 1) A new substance is created 2) The properties of the new substance are different from the substances that you started with 3) No atoms are created or destroyed during chemical reactions 4) Atomic bonds are broken and new bonds are formed (at the valence electron level) 5) compounds come from chemical reactions SPI Chemical Change Outcomes Notes Science

Chemical Change Indicators-Memory Trick H.O.P.E. H: Heat-Heat may be given off (it may get hot) O: Odor-There may be a change in odor (how it smells) P: Pop-It may pop or bang (make a loud noise) E: Explode-It may explode (like fire crackers or dynamite) SPI Chemical Change Outcomes Notes Science Memory Trick Chemical reactions can H.O.P.E.

Chemical Change Indicators-Memory Trick 4FPC F: Foam-It may foam (like vinegar & baking soda) F: Flash-It may flash (like a grenade or gun powder) F: Fizzle-It may fizzle (make a hissing sound like Alka-Seltzer) F: Flame- It may burn (like burning paper or wood) P: Precipitate-It may form a solid substance (called a precipitate) C: Color- It may change color (red to blue, green to orange, etc.) SPI Chemical Change Outcomes Notes Science Memory Trick Chemical reactions can 4FPC