Isotopes and Atoms

What Does the Periodic Table Reveal:

The above image shows that the element Krypton has: 

• An atomic number of 36 
• 36 Protons in the nucleus 
• An atomic mass of 83.80 
• This atomic mass is the weighted average of the mass of all the isotopes   
• It also reveals the number of neutrons  
• Atomic Mass(84) - Atomic Number/ Number of Protons(36) 
• 48 neutrons in the nucleus

What are Isotopes:

Isotopes are any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different number of neutrons in the nucleus, or different atomic weights. 


For example, there are three types of hydrogen: 

• Hydrogen (Atomic Number: 1/ Atomic Mass: 1)
• Deuterium (Atomic Number: 1/ Atomic Mass: 2)
• Tritium (Atomic Number: 1/ Atomic Mass: 3)    

As you can see, each of these different types of hydrogen have identical atomic numbers, therefore the number of protons in the nucleus is consistent. However, the distinction lies in their different atomic mass or the difference in neutrons. These are isotopes. 

What are Mass Spectrometers: 

Mass spectrometers are graphs used to determine the abundance and mass of the isotopes of an element. In these graphs the y-axis charts the relative abundance versus the mass in the x-axis. If the relative abundance is multiplied by the mass, as identified in each isotope, and this is done for all the other isotopes of an element, the abundance can be calculated to 100%. 

For example, zirconium: 

(relative mass x mass) + (relative mass x mass)... 

(0.515 x 90.00) + (0.112 x 91.00) + (0.171 x 92.00) + (0.174 x 94.00) + (0.0280 x 96.00)

 = 91.3 amu or 91.3 atomic mass units 


-Simon Sierra