Isotopes Notes.pdf, Exams of Chemistry

Download Isotopes Notes.pdf and more Exams Chemistry in PDF only on Docsity! Isotopes Copy the slide when you see... Each element has a unique # of protons. So…EVERY SINGLE ATOM of that element MUST HAVE the SAME number of protons, ALWAYS! This is the reason why each element has a unique Atomic Number that never changes! There are 3 isotopes carbon: How many protons does each isotope have? How many neutrons does each isotope have? 6 C Carbon 12 6 C Carbon 13 6 C Carbon 14ALL carbon isotopes have an atomic # of 6, so they all have 6 protons! 6 neutrons 7 neutrons 8 neutrons Atomic Masses on the periodic table are normally decimals. WHY?? Atomic Masses are decimals because it is an AVERAGE mass of all of the element’s isotopes. Some isotopes are more common than others, so this is a weighted average. So the Mass # from the periodic table is always closest to the most common isotope’s mass. 5 B Boron 10.81 In the universe, there are MUCH more carbon-12 atoms that exist than carbon-13 and carbon-14 atoms. When you find the weighted average of the masses of the carbon isotopes, the average will be closest to 12! 6 C Carbon 12.01 Carbon- 12