1. Do you know the first 20 elements and their symbol?
The Elements.
Do you know the first 20 elements and their symbol?

2. Recap Atoms have a positively charged nucleus containing protons.
The nucleus also contains neutral charged neutrons.
Electrons surround the nucleus in “shells”

3. What determines an Element?
The number of protons inside an atom determine which element it is.
1 proton mean Hydrogen.
2 protons means Helium.
So forth and so on.

4. Atomic Charge Protons are + Electrons are – Neutrons are +/-
An atom prefers to be neutral thus having a net charge of zero.
The number of electrons starts out equaling the number of protons.

5. Atomic Number The number of protons in an atom.
Oxygen has an atomic number of 8. What does that tell me about the number of protons it has?

6. The mass of these little guys.
Protons and Neutrons have a mass of 1 atomic mass unit (amu)
The mass of an electron is 1/ 1836 the mass of a proton, thus insignificant.

7. Atomic Mass
The atomic mass is the total number of proton plus total number of neutrons inside an atom.
Protons + Neutrons = Atomic Mass

8. How to write them.

9. Atomic Mass
What is the atomic number, atomic mass, number of protons, and number of neutrons?
Starting out, how many electrons will this atom have?

10. Atomic Mass
What is the atomic number, atomic mass, number of protons, and number of neutrons?
Starting out, how many electrons will this atom have?

11. Isotopes
An atomic with the same number of protons and a different number of neutrons.

12. Future Assignment:
I want you to know the chemical symbol and name of the first 20 elements and (Silver, Gold, Mercury, Lead, and Uranium)