1. Learning objective 2: I can understand the patterns found in the number of protons, neutrons, and electrons in an atom.

2. What is everything made out of? What can something be made of?

3. Each different type of atom is called an element, and they are organized into a table…
The Periodic Table of the Elements contains every possible atom so far discovered.

4. Using the periodic table

7. The atomic number tells you how many protons are in that atom
Protons are the identity of an atom, adding or subtracting protons gives you a different element

8. So, we know carbon has 6 protons. How many electrons does it have?
It must have 6, because an atom is always neutral. So the atomic number is really the number of protons and also the number of electrons

9. Atomic mass is how much mass the atom has. How can we use this?

10. Subatomic Particle
Charge
Location
Size/Weight
Proton
Positive (+)
Nucleus or “Core”
Large/1 au
Neutron
No Charge (0)
Electron
Negative (-)
Electron Cloud
Small/0 au

11. Protons and neutrons are the only parts that have any mass, so the atomic mass is the number of protons and neutrons added up.

12. Atomic weight (rounded) — number of protons = number of neutrons
So, there are 6 protons, weighing 1 au each. How many neutrons must there be?
Atomic weight (rounded) — number of protons = number of neutrons
12 total — 6 protons = 6 neutrons
Note: the numbers of protons and neutrons won’t always be equal

13. Sometimes, the element’s box won’t look quite the same

14. It may look like this…
Atomic number
Symbol
Atomic mass
Name

15. Name
Atomic number
Symbol
Atomic mass

16. Atomic number Symbol Name Atomic mass
Don’t worry about this, you’ll learn it in high school
Symbol
Name
Atomic mass

17. Time for some practice!