1. Atomic Calculations and Mass Spectrometry
Quantum Orbital Video

2. Atomic Mass – Atomic Number = # Neutrons
(p + n) (p) = (n)

3. Complete the following chart:
protons electrons neutrons H Zr
Ca2+
P3-
Al3+
Cl-

4. Isotopes- same atomic number but different mass
For example, there are 3 types of hydrogen atoms.
1H H H
Not all atoms of the same element are identical.

5. Mass Spectrometers
   
Are used to determine the abundance and mass of the isotopes of elements

8. Mass Spectrometers
A device known as a mass spectrometer can be used to determine the relative abundance and the mass of the isotopes of elements. 
In the graph the isotopes of a sample of the element zirconium can be seen in their relative abundances.

9. The data can be summarized as follows:
      Isotope            Mass` Abundance
      90Zr amu              %
      91Zr amu               %
      92Zr amu               %
      94Zr amu               %
      96Zr amu              %
       atomic mass of isotope                  100 %

10. Calculate the weighted average mass of zirconium using the data above.  
Change each percent to a decimal by dividing by 100.
Multiply by the mass.
Add it all together.
0.515(90.00)
(91.00)
(92.00)
(94.00)
(96.00)
= 91.3 amu
3 sig figs!
Look up the mass on the periodic chart.
The unit amu describes how many times heavier than the mass of H
= 91.2 amu
They are the same with uncertainty

11. Calculate the average atomic mass for Germanium
36.54 %
amu
27.43 %
amu
20.52 %
amu
7.76 %
amu
7.76 %
amu
(0.2052)( ) + (0.2743)( ) + (0.0776)( ) + (0.3654)( ) + (0.0776)( ) =
= 72.6 amu
Periodic Table = 72.6 amu

12. Quantum orbitals