1. How do the parts of an atom influence the elements?

2. Recap
Atoms have a positively charged nucleus that contains both protons and neutrons.
Electrons orbit around the nucleus in a “cloud”

3. What determines an Element?
The number of protons inside an atom determine which element it is.
1 proton means Hydrogen.
2 protons means Helium.
What element has 15 protons?

4. Atomic Charge Protons are + Electrons are – Neutrons are neutral
An atom prefers to be neutral thus having a net charge of zero.

5. Atomic Number
The number of protons in an atom.

6. Atomic Number O
Atomic Number
Oxygen has an atomic number of 8. What does that tell me about the number of protons it has?

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

8. Mass Number O
Mass Number

9. How do we find the number of neutrons?
Number of neutrons = Mass number – Atomic number OR
Number of neutrons = (# neutrons + # protons) – (# protons)
So….how many neutrons does Chromium (Cr) have?

10. How do we determine the number of electrons?
Number of electrons = number of protons

11. Atomic Mass
What is the atomic number, atomic mass, number of protons, number of neutrons, and number of electrons of the following element? 30 Zn
65.39

12. Isotopes
An atom with the same number of protons and a different number of neutrons.