1. Bellwork or
Teacher’s Pet – Atoms: Write 3 facts for the video.

2. Atomic Structure

3. The Atom
Smallest form of an element that still retains that elements properties
Basic building block of matter
Made of:
Protons
Neutrons
Electrons

4. The Atom
Composed of:
Nucleus
Electron Cloud

5. The Nucleus Positively charged Protons and neutrons
Protons – positively charged
Neutrons – neutrally charged

6. The Electrons Negatively charged
Occupy the “Electron cloud” surrounding the nucleus
Arranged into shells or orbitals
Electrons are NOT moving in perfect orbits around the nucleus. The electron movement is unpredictable
Cloud gives us approximate location of where electrons are

8. Subatomic Particles Location Charge Mass Special Fact Protons Nucleus
Positive (+)
1 amu
Number of protons determines the identity of the element
Neutrons
Neutral
Electrons
Electron Cloud
Negative (-)
amu
Electron cloud takes up % of the volume of the atom

9. Properties of Atoms
Atomic Number
Mass Number
Average Atomic Mass

10. INSIDE THE SQUARES…

11. Atomic Number Number of protons in the nucleus of an atom
Each element has its own specific atomic number
In a NEUTRAL ATOM, this is also the number of electrons

12. (Average) Atomic Mass
An average mass of each of the different isotopes found for that element in nature
For example, Chlorine has 2 different isotopes
Each one has 17 protons and a different number of neutrons (This is what an isotope is. More on that later)
If you take the average atomic mass of every
single chlorine atom that
exists, the average mass
will be amu

13. Mass Number Mass number is the mass of a SPECIFIC isotope of an atom.
It is the SUM of the protons and neutrons in the nucleus
Mass Number = (# of neutrons) + (# of protons)
Mass Number = Atomic Mass
It is not the average unless we say AVERAGE
How do we find # of
neutrons?

14. So how do I know what the Mass Number is?
I will tell you. One of two ways:
1) Give you the mass number or the neutrons in a table.
If I don’t give it to you, get the rounded # off the Periodic Table
2) Tell you in the symbol.
Isotope Notation:
Isotope Name:
Sodium-23

15. Figuring out some element parts…
Symbol
Atomic #
Protons
Neutrons
Mass #
Boron-11 B
Carbon -12 6
Magnesium-23 12 23
Copper-64 29 35 20

16. Figuring out some element parts…
Symbol
Atomic #
Protons
Neutrons
Mass #
Boron-11 B 5 6 11
Carbon -12 C 12
Magnesium-23 Mg 23
Copper-64 Cu 29 35 64 ? 20

17. Closure in Composition Notebook
How do you find the atomic number of an element?
 How do you find the number of protons of an element?
 How do you find the number of electrons of an element?
 How do you find the number of neutrons of an element?
 How do you find the atomic mass of an element?
Homework: Complete the Atomic Structure Practice I for homework.
Staple this in your composition next class meeting.