1. Pg 29 Header: I can calculate mass number for isotopes Title: Isotopes

2. What is an isotope?
Two atoms with equal protons but different neutrons are called isotopes of each other.
All atoms in existence are isotopes! Some isotopes are just more common than others.

3. X A Z Isotope Notation Mass number
= number of protons + number of neutrons A X
Element symbol Z
Atomic number
= number of protons

4. X A Z A – Z = number of neutrons
Number of neutrons = Mass Number – Atomic Number

5. Hyphen Notation
Write out the name of the element, then add a hyphen (-), then the mass number.
Example: Chlorine-35

6. Isotopes
Isotopes: atoms with equal protons but different number of neutrons
DRAW this in your notes – use colored pencils

7. Isotope Notation
Write each of these cases, in isotope notation under the picture that you draw!

8. Hyphen Notation
Now, write the hyphen notation for the three isotopes of hydrogen in your drawings above.
Isotope Notation
Hyphen Notation
hydrogen-1
hydrogen-2
hydrogen-3

9. U U 235 92 238 92 Mass number Atomic number Mass number Atomic number
Examples of uranium isotopes:
Glue in and answer questions! U
235 92 U
238 92
Mass number
Atomic number
Number of protons
Number of neutrons
Mass number
Atomic number
Number of protons
Number of neutrons

10. U U 235 92 238 92 Mass number 235 Atomic number 92 143 Mass number 238
Now, check your answers! U
235 92 U
238 92
Mass number
235
Atomic number 92
Number of protons
Number of neutrons
143
Mass number
238
Atomic number 92
Number of protons
Number of neutrons
146
Isotopes of any particular element contain the same number of protons, but different numbers of neutrons.

11. Pg 30: I can characterize ions
Title: Ions

12. Ions Ions are charged particles. They are positive or negative
Ions Ions are charged particles. They are positive or negative. Different number of p+ and e-

13. Anions & Cations Cation: A PAWsitive ion. Anion: A negative ion.
Example: Na+1
Anion: A negative ion.
Example: Cl-1

14. Ions’ charges come from changes in ELECTRONS only!
Ions have charges!
Draw these examples of ions in your Comp Book!
Charge: -1 +1
Ions’ charges come from changes in ELECTRONS only!

15. Final Facts All atoms and ions are isotopes. All ions are charged.
All atoms are neutral.
Ions are also isotopes!

16. Worksheet Go back through your petri dishes from yesterday
Fill in ALL the boxes

17. Ion Practice Do this in your Comp Book to practice
Example #1: How many p+ and e- does each have? Ni
Sr +2
Br -1

18. Heavy vs. Light Isotopes
To determine if an isotope is heavy or light….
Compare the mass number to the average atomic mass on the periodic table for that element.
If the mass number is higher, it is HEAVY
If the mass number is lower, it is LIGHT
If the mass number is within .5 amu of the atomic mass, it is AVERAGE

19. Heavy vs. Light Isotopes
Example 1: Calcium-41
Example 2: Sodium-22
Example 3: Chromium-52