1. Atomic Calculations and Mass Spectrometry Quantum Orbital Video

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

4. Complete the following chart: protonselectronsneutrons H Zr Ca 2+ P 3- Al 3+ Cl - 110110 404051 201820 151816 131014 171819

5. Isotopes- same atomic number but different mass Not all atoms of the same element are identical. For example, there are 3 types of hydrogen atoms. 1 H 2 H 3 H

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

9. 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.

10. The data can be summarized as follows: Isotope Mass`Abundance 90 Zr90.00 amu 51.5 % 91 Zr91.00 amu 11.2 % 92 Zr92.00 amu 17.1 % 94 Zr94.00 amu 17.4 % 96 Zr96.00 amu 2.80 % atomic mass of isotope 100 %

11. 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. + 0.0280(96.00)+ 0.174(94.00)+ 0.171(92.00)+ 0.112(91.00)0.515(90.00) =91.3 amu3 sig figs! Look up the mass on the periodic chart. They are the same with uncertainty =91.2 amu The unit amu describes how many times heavier than the mass of H

12. Calculate the average atomic mass for Germanium 20.52 % 69.92428 amu 27.43 % 71.92174 amu 7.76 % 72.9234 amu 36.54 % 73.92115 amu 7.76 % 75.9214 amu (0.2052)(69.92428) + (0.2743)(71.92174) + (0.0776)(72.9234) + (0.3654)(73.92115) + (0.0776)(75.9214) = =72.6 amu Periodic Table=72.6 amu

13. Quantum orbitals