1. The Structure of the Atom

2. 1.The Atom a. “the building blocks” of all matter b. Particles that make up the atom: 1.Nucleus a. “core” of the atom b. 99.9 % of the mass c. Yet the nucleus is nearly 100,000 times smaller than the rest of the atom. example: a bee compared to a football stadium.

3. d.Protons 1.Positive Charge 2. p + 3. mass of a proton = 1 amu (atomic mass unit) e. Neutrons 1. Neutral Charge 2. n 3. slightly more mass than protons, but still considered 1 amu.

4. 2. Atomic Number a. # of protons in the nucleus b. Identifies the element ex. H = 1 Mg = 12 c. Since + and - charges are normally equal, it is also the number of electrons.

5. 3. Mass Number, Atomic Mass, & Isotopes a. Mass Number = protons + neutrons b. Atomic Mass is the average mass of all existing isotopes of a given element.

6. c. Isotopes - Atoms of the same element that have the same # of protons, but a different # neutrons. How many neutrons are in Carbon 12, 13, and 14?

7. 5. The Electron a.1/2000 the size of a proton or neutron. b. Negative charge c. Electron Cloud- the space that electrons are likely to be found.

8. If an electron weighed the same as a dime, a proton would weigh the same as a gallon of milk. Size of an Electron vs Proton

9. If this were the proton in a hydrogen atom, it would take a screen 1 mile across to display the electron's orbit. Size of an Atom