atomic calculations and mass spectrometry
DESCRIPTION
Atomic Calculations and Mass Spectrometry. Quantum Orbital Video. Atomic Mass – Atomic Number = # Neutrons (p + n) - (p) = (n). 110. Complete the following chart: protonselectronsneutrons H Zr Ca 2+ P 3- Al 3+ Cl -. 404051. 201820. - PowerPoint PPT PresentationTRANSCRIPT
Atomic Calculations and Mass Spectrometry
Quantum Orbital Video
Atomic Mass – Atomic Number = # Neutrons
(p + n) - (p) = (n)
Complete the following chart:
protons electrons neutrons
H
Zr
Ca2+
P3-
Al3+
Cl-
1 1 040 40 51
20 18 2015 18 16
13 10 14
17 18 19
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.
1H 2H 3H
Mass Spectrometers Are used to determine the abundance and mass of the isotopes of elements
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.
The data can be summarized as follows: Isotope Mass` Abundance 90Zr 90.00 amu 51.5 % 91Zr 91.00 amu 11.2 % 92Zr 92.00 amu 17.1 % 94Zr 94.00 amu 17.4 % 96Zr 96.00 amu 2.80 % atomic mass of isotope 100 %
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 amu 3 sig figs!
Look up the mass on the periodic chart.
They are the same with uncertainty
= 91.2 amuThe unit amu describes how many times heavier than the mass of H
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
Quantum orbitals