1. ISOTOPES AND ATOMIC MASS
Chem-To-Go Lesson 6
Unit 2

2. Quick review PROTON NEUTRON ELECTRON Has mass Found in the nucleus
Has no mass
Found outside the nucleus

3. Why are all three atoms considered to be hydrogen?
Isotope illustration
𝟏 𝟏 𝐇
𝟏 𝟐 𝐇
𝟏 𝟑 𝐇
Hydrogen-1
Hydrogen-2
Hydrogen-3
Why are all three atoms considered to be hydrogen?
Definition of Isotope: Atoms of the same element that have different masses because of differing numbers of neutrons (therefore different mass numbers)

4. Prevalence of isotopes
All of these blocks are called Legos, but they are not all identical to one another.
Most elements have several isotopes.

5. Atomic Mass
If there are THREE different types of magnesium atoms, which ONE is represented on the periodic table?
Answer: None! The block represents the average magnesium atom.
Huh? No magnesium atom actually weighs amu. All of the different types of magnesium atoms were averaged, and an average Mg atom weighs amu.

6. Calculating atomic mass
Atomic Mass = [(decimal abundance)(mass)] + [(decimal abundance)(mass)] + [(decimal abundance)(mass)] + …

7. Calculating atomic mass
Atomic Mass = [(decimal abundance)(mass)] + [(decimal abundance)(mass)] + [(decimal abundance)(mass)] + …