1. Mrs. “Chemistry is the fun stuff” Burge
ATOMS!!!!
Mrs. “Chemistry is the fun stuff” Burge

2. Atoms
Atom- the smallest particle of an element that retains the elements properties
Remember an element is only made of one kind of atoms
Anything made of iron is made only of iron atoms

3. Parts of an atom An atom is made up of 3 different parts:
Protons- +, positively charged particle that remains in the center of the atoms
Each proton has a 1+ charge
Neutrons- neutral charged, or non charged particles that remain in the center of the atom
Electrons- -, negatively charged particles that orbit the atom
Each electron has a 1- charge
Extremely small, smaller than other 2 particles and do not affect atomic mass

4. Parts of an atom An atom has 2 different sections:
Nucleus- positively charged center of the atom
The nucleus contains proton and neutrons
Electron Cloud- negatively charged outer area of the atom
Electrons orbit the nucleus in this area
100,000 times larger in diameter than the diameter of the nucleus

5. Quarks
Quarks are even smaller particles that make up Protons and Neutrons
Electrons are not made up of smaller particles
Scientists continue to try and learn more about Quarks everyday
They use atom accelerators to cause collisions that break the protons and neutrons apart
Their efforts are trying to find new particles and to try and further their explanations for how the universe was formed

6. Dalton’s Atomic Model Dalton’s Atomic Model consists of 6 parts:
Matter is composed of extremely small particles called atoms
Atoms are indivisible and indestructible (somewhat)
Different atoms combine in simple whole number ratios to form compounds
In chemical reactions, atoms are separated, combined or rearranged

7. Rutherford Gold Experiment
Rutherford sent radiation through a piece of gold foil and found that some particles passed through, some were scattered and some bounced back
This showed that atoms have empty space and other areas of high concentration of matter

8. Atomic Number This is DIFFERENT than the Atomic Mass/Mass number
This is the number of protons the atom has
The protons are what change an atom into a different element
Each element can have different number of neutrons and electrons but will always the same number of protons

9. Mass Number
The mass number of an atom is the sum of the number of protons and neutrons in the nucleus of the atom
Mass # = #of protons + #of neutrons

10. Isotopes
Isotopes are atoms of the same element (have the same number of protons) but have a different number of neutrons
To identify isotopes we put the mass number in the name of element
Example: Carbon-12, Carbon-14 (radioactive)

11. Atomic Mass Atomic mass is the mass of an atom
Only protons and neutrons are counted because electrons are too small
Protons = 1.67*10-24
Neutrons = 1.67*10-24
Electrons = 9.1*10-28
What do these numbers mean?
Atomic mass is contained almost entirely in the nucleus of the atom
Measured in unit called (amu) = atomic mass unit

12. Average Atomic Mass
The average atomic mass is the weighted average mass of all the naturally occurring isotopes of an element
Takes into account how often each isotope occurs
This is why the atomic mass on the periodic table is not a whole number (has decimals)

13. Elements on the Periodic Table