Transcript Notes-Atoms & Chem Reactions

Notes
SPI 0807.9.1
Atoms
Science
 We once thought atoms were the smallest particles.
 We now know there are even smaller particles
 They are called sub-atomic particles
(protons, neutrons, and electrons)
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
4
Be
Beryllium
9.0
Legend
=protons
=neutrons
=electrons
SPI 0807.9.1
Atoms
Notes
Science
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)
3
Li
Lithium
6.9
Here is a model of
a lithium atom
Notes
SPI 0807.9.1
Atoms
Science
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
Legend
=protons
=neutrons
=electrons
Nucleus
Notes
SPI 0807.9.1
Atoms
Science
 Electrons are located in the electron cloud in areas
called electron shells (see cloud in green area below)
 This atom has 2 electron shells. These can also be
called electron energy levels or electron orbitals.
1st Shell
Legend
The green area is
the electron cloud
area
=protons
=neutrons
=electrons
2nd Shell
Nucleus
Notes
SPI 0807.9.2
Chemical Change Outcomes
Science
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
Notes
SPI 0807.9.2
Chemical Change Outcomes
Science
Compounds
Compounds are formed from chemical reactions
Memory Trick
C=C
(chemical reactions = compounds)
Example: When two hydrogen atoms react with one oxygen
atom you produce (form) the compound called water (H2O).
H
Oxygen
H
Oxygen
H
H
Notes
SPI 0807.9.2
Chemical Change Outcomes
Science
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
Notes
SPI 0807.9.2
Chemical Change Outcomes
Science
Memory Trick
Chemical reactions can H.O.P.E.
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)
Notes
SPI 0807.9.2
Chemical Change Outcomes
Science
Memory Trick
Chemical reactions can 4FPC
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.)