1. Isotopes
All atoms of an element have the same number of protons. However, they can have a different number of neutrons. What do we call an atom when they have the same # of protons, but a different # of neutrons? ISOTOPES Lets Explore Isotopes…

2. There are a different # of protons & neutrons.
KEY:
Green = Protons
Red = Neutrons
This nucleus is NOT an isotope because there are the same # of protons & neutrons.
ISOTOPE!
There are a different # of protons & neutrons.
Let’s get a closer look…

3. If an atom has a MISSING neutron or an EXTRA neutron:
ISOTOPE!
They are still the same element. They are just a little different from every other atom of the same element.

4. HYDROGEN
Hydrogen has 1 proton. THIS WILL NEVER CHANGE! (If there are 2 protons, it isn’t hydrogen!)
Most Hydrogen have no neutrons.
1 proton & 1 neutron = Hydrogen isotope 1 proton & 2 neutrons = Hydrogen isotope
**The “1 proton” tells us it is hydrogen. Having neutrons tells us it is an isotope.**

5. FIND THE ISOTOPE(S)… Carbon
In nature, ALL carbon have 6 protons. Most carbon have 6 neutrons.
6 proton + 6 neutron
6 proton + 7 neutron
6 proton + 12 neutron
FIND THE ISOTOPE(S)…

6. Carbon WHY ARE THEY ISOTOPES?
In nature, ALL carbon have 6 protons. Most carbon have 6 neutrons.
6 proton + 6 neutron
6 proton + 7 neutron
6 proton + 12 neutron
WHY ARE THEY ISOTOPES?

7. In nature, ALL carbon have 6 protons. Most carbon have 6 neutrons.
6 proton + 6 neutron
6 proton + 7 neutron
6 proton + 12 neutron
Because they have a different # of neutrons then what normally happens in nature.

8. How are we supposed to know what normally happens in nature???
Excellent question. Let’s go over how to read one
element box on the Periodic Table of Elements.

9. (sometimes called Atomic Mass)
Element Name
Atomic Number
(# of protons)
Element Symbol
Mass Number
(sometimes called Atomic Mass)

10. You know how to find the number of neutrons…
Subtract the # of protons from the Mass Number (rounded).
12 – 6 = 6 Neutrons
So, 6 protons & 6 neutrons are the “normal” amounts of each found in nature.

11. Carbon
ISOTOPE:
6 protons
8 neutrons
Mass=14
Carbon:
6 protons
6 neutrons
Mass=12

12. How do I know if it is a “regular” element or an isotope??
Use the Periodic Table of Elements as your baseline.
Calculate # neutrons for the element. (Mass – Protons = Neutrons)
Then look to see if your Element has more neutrons than the same element on the Periodic Table.
That’s it! If it has LESS or MORE neutrons – ISOTOPE!

13. Carbon on the Periodic Table has a Mass Number of 12 and 6 protons.
Which one of these are ISOTOPES?

14. Carbon on the Periodic Table has a Mass Number of 12 and 6 protons.
12 – 6 = 6 Neutrons
13 – 6 = 7 Neutrons
ISOTOPES
14 – 6 = 8 Neutrons

15. Questions? Ask Mrs. Cancel or another student to help clarify.
This is a REALLY easy concept. If an element has more or less neutrons than the same element on the periodic chart – ISOTOPE.
Questions? Ask Mrs. Cancel or another student to help clarify.