1. Atomic Structure Bellringer: What is the charge of the following:
Protons, Electrons, and neutrons?
Objective:
SWBAT describe the structure of an atom.
SWBAT use atomic # and mass to calculate the # of subatomic partices

2. ATOMIC STRUCTURE
Particle
Charge
proton
+ charge
neutron
No charge
electron
- charge

3. HELIUM ATOM + - + - Shell proton neutron electron
What do these particles consist of?

4. ATOMIC STRUCTURE Particle Charge Mass proton 1 neutron 1 electron nil
+ (positive) charge
neutron
No charge 1
- (Negative) charge
electron
nil

5. Atomic Mass Units
We use Atomic Mass Units (amu) to measure the mass of atomic particles.
1 amu = (73)×10−27 kg kg

6. Goal: Draw a Bohr Model of an Atom
Steps:
Determine the number of protons, neutrons, and electrons.
Draw nucleus with protons and neutrons
Draw electrons in proper orbitals
We use the Bohr model because it’s the only good way to represent an atom and it’s electrons on paper.

7. Step 1: Determine the number of protons, neutrons, and electrons
How do we know how many protons, neutrons, and electrons an atom of an element has?

8. He 2 4 ATOMIC STRUCTURE number of electrons = number of protons
Atomic number
the number of protons in an atom 4
Atomic mass
the number of protons and
neutrons in an atom
number of electrons = number of protons
Atomic Mass – Atomic Number = # or Neutrons

9. Guided Practice: H: Hydrogen Atomic Number = _____
ATOMIC STRUCTURE
Guided Practice:
H: Hydrogen
Atomic Number = _____
# of protons = _____
# of electrons = _____
Atomic Mass = _____
# of neutrons = ____ 1 1 1 1

10. Guided Practice: He: Helium Atomic Number = _____ # of protons = _____
ATOMIC STRUCTURE
Guided Practice:
He: Helium
Atomic Number = _____
# of protons = _____
# of electrons = _____
Atomic Mass = _____
# of neutrons = ____ 2 2 2 4 2

11. Guided Practice: Li: Lithium Atomic Number = _____
ATOMIC STRUCTURE
Guided Practice:
Li: Lithium
Atomic Number = _____
# of protons = _____
# of electrons = _____
Atomic Mass = _____
# of neutrons = ____ 3 3 3 7 4

12. Or + = + = Step 2: Draw nucleus with protons and neutrons He:

13. Guided Practice H:
Protons = 1
Neutrons = 0
P = 1
N = 0 + Or

14. = + = + = + = Or Guided Practice Li: Protons = 3 Neutrons = 4 P = 3

15. How do we know where to put the electrons?
Step 3: Draw the electons in the electron orbitals
How do we know where to put the electrons?

16. Fill up the lowest orbital before moving to next!!
Electrons are arranged in Energy Levels or Shells around the nucleus of an atom.
first shell a maximum of 2 electrons
second shell a maximum of 8 electrons
third shell a maximum of 8 electrons
fourth shell a maximum of 18 electrons
fifth shell a maximum of 18 electrons
sixth shell a maximum of 32 electrons
Fill up the lowest orbital before moving to next!!

17. Or + = + = Step 3: Draw electrons in electron in orbitals - - He:

18. Guided Practice - - H:
Electrons = 1
P = 1
N = 0 + Or

19. = + = + = + = Or Guided Practice - Li: Electrons = 3 - - - - - P = 3

20. Assigned Practice
Due tomorrow!!