1. How did Rutherford conclude that he found a positive nucleus?
Drill
How did Rutherford conclude that he found a positive nucleus?

2. Agenda Notes about Atoms Drill Build an atom simulation HW Handout
Post Test
Notes about Atoms HW

3. Build an Atom Simulation
Google “phet build an atom”
Complete the handout
Complete the Post Test
Place in bin
Start to work on Review Packet! 

4. Atoms
Atomic Number
Periodic table is arranged in increasing atomic number
Equals the number of protons in the atom
Used to identify the atom
Every atom of an element will have the same atomic number and thus the same proton number

5. Review How can you find the number of protons?
Find the element’s atomic number on the periodic table
Practice: Identify the number of protons Cr Li

6. Review How can you find the element from the number of protons?
Find the atomic number on the periodic table
Identify the element
13 protons
2 protons

7. Check In
How many protons does Oxygen (O) have? 8 16 6 76

8. Isotopic Notation Isotopes
Atoms of the same element (same protons) with different masses due to having different neutrons amounts

9. Isotopic Notation
A = mass number
Z = atomic number
X = element symbol

10. Element – Y
Y = mass number

11. Mass Number Mass Number = Protons + Neutrons
If you know any two pieces of the equation, you can solve for the third

12. Review How can you find the number of neutrons?
Find mass number: Mass number – protons
Find the number of neutrons:
Zinc-65
Oxygen-16
Find the mass number:
Boron, 6 neutrons
7 protons, 7 electrons, 5 neutrons

13. Check In
How many neutrons does Chlorine – 37 have? 17 35 37 20

14. Atomic Charge In neutral atoms, electrons = protons
Electrons are negative
If you gain electrons, you increase the atom’s “negativity” and the charge becomes more negative
Add 2 electrons, charge = -2

15. If there is a charge, this is known as an ion
If you lose electrons, you decrease the atom’s “negativity” and the charge becomes more positive.
Take away 1 electron, charge = +1
If there is a charge, this is known as an ion

16. Find the charge 3 protons, 2 electrons = 8 protons, 10 electrons =

17. How many electrons?
Ca+2
P-3

18. Check In
How many electrons does Se-2 have? 34 36 78 2

19. Complete Parts 1 and 2 on Isotope HW
**Make sure I have Post-Test in Bin!!

20. Isotopic Notation 21 Sc 46 = mass number 21 = atomic number
(the total number of protons (21) and neutrons (25)
21 = atomic number
(the total number of protons (21))
Sc = element symbol
This atom is neutral, the number of electrons (21) is equal to the number of protons

21. Isotopic Notation 21 Sc-1 46 46 = mass number 21 = atomic number
The total number of protons (21) and neutrons (25)
21 = atomic number
The total number of protons (21)
Sc = element symbol
This atom is charged, the number of electrons (22) is equal to protons +1 more electron