Download Science Notes September 09/06/2016

Science Notes September
09/06/2016 - 09/30/2016
9/7
Discussion questions to think about today
How is a piece of foil similar to an atom?
What is an atom?
How small is an atom?
Can you keep cutting the foil in half? (What was your limitation?)
NO, may depends on the size of the scissors
You would need a smaller or finer scissors to cut it smaller
Ultimately you couldn't hold it and then couldn't see it
If you couldn't cut it down anymore it would be an ATOM!
(Extremely tiny tiny tiny!)
9/8 - Periodic tables are ALL set up the same (colors may be different)
It works like a grid (find column and row to find elements)
CO vs CO2
Carbon monoxide vs Carbon dioxide
They differ because of the number 2
H2O vs H2O2
Water vs hydrogen peroxide
Discussion question
How big is an atom?
1 millimeters (mm) = 1,000,000 nanometers (nm)
1 centimeter (cm) = 10 millimeters (mm)
9/9 - what is the purpose of the election microscope?
To see very tiny things
How is an election microscope different from a compound microscope?
You can get more details from an election microscope and it is like using a vacuum (nothing inside)
Compound microscope uses light to make the item bigger
Why do we need models to represent atoms?
We can show people what an atom looks like to visually understand
Example from Notes on How Big is an Atom?
Human red blood cell
6,000 Diameter of object
______________________
0.1 nm diameter of atom
Example of scientific notation
5000 = 5x10 to the third
(diameter of object divided by diameter of atom)
9/16 - 3 parts to every atom
Protons +
Neutrons neutral/no charge
Electrons Protons and neutrons are about the same size
Electrons small in the atom
Protons and neutrons are located in the center of the atom (nucleus)
Electrons are on the outside of the atom
Elements
number of protons changes the element /element number
periodic table organized by the number of protons in the nucleus
subatomic particles are protons and neutrons have mass
electrons no mass
Neutrons balances the stability of an atom
Adding mass stabilize atom
Ion in an atom or a molecule - the total number of electrons is not equal to the total number of protons the atom or molecule a net positive or negative electrical charge
Chart
Protons
Neutrons
Electrons
Location
Nucleus
Nucleus
Outside
Mass
Yes
Yes
No
Charge
Positive
Neutral
Negative
9/19/16 Atomic Model - Ions
More protons than electrons - positive charge
More electrons than protons - negative charge
Scientists built upon idea of an atom Democritus - first person - studied an atom
…Believed an object still exists even if not visible to eye and indivisible
Dalton expanded into elements classification chart called periodic table with different masses & properties
…Everything may be split into atoms (smallest particles) & compounds – combinations of elements
JJ Thomson experimented with rays/beams of light to determine - electrons hold negative charge - plumb pudding
model
Rufford used gold foil to prove his theory (some of the partials bounced back) expanded on plumb pudding model
electrons (negative charge) around (positive charge) proton environment (nucleus)
Bohr discovered electrons exist at certain energy levels
… are different colors lights in different elements & connection between light and atoms
…electrons small negatively charged; protons in nucleus; element absorbs certain light colors
Atomic mass
Protons - 1 atomic mass unit (amu)
Neurons - 1 atomic mass unit (amu)
Electrons - 1/2000 atomic mass unit
Atomic mass = protons + neutrons
Example
Lithium - 3 protons - 3 electrons - 3 neutrons
The atomic mass = 6
Average Atomic mass - average actual atoms that exist in nature and the percentage of each type
Neutrons - atomic mass subtract the atomic number (protons) = neutrons