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Sub atomic heavyweights. Pictures and Notes. Isotope. Is a variation in the number of neutrons found in the atom of a specific element Different isotopes of the same element have different numbers of neutrons and therefore different atomic masses
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Sub atomic heavyweights Pictures and Notes
Isotope Is a variation in the number of neutrons found in the atom of a specific element Different isotopes of the same element have different numbers of neutrons and therefore different atomic masses Every different version of an element is considered a different isotope
Number of isotopes of an element Not set number Most elements average between 2-10 The stability of isotopes varies greatly, those that are not stable, decay after the passing of time (RADIOACTIVITY)
DETERMINE THE ATOMIC MASS OF AN ELEMENT’S MOST COMMON ISOTOPE
Round atomic weight (average atomic mass) to nearest whole number
Ion vs isotope If the # protons change, a new element is created If the # neutrons change, a new isotope of the same element is created If the # of electrons change, the element is ionized
Chemical properties of Isotopes • It is important to remember that isotopes of the same element behave the same way in chemical reactions since they have the same number of protons and electrons.
Carbon 14 1 out of every trillion atoms Created by the sun, by gamma rays hitting nitrogen-15 Not natural Important isotope used to help date fossils of humans
Isotope names Two ways 1st: list the name or symbol of the element and the atomic mass of the isotope: Ex Uranium-237, U-238 • Write symbol of element and place the atomic mass on top and the atomic number below Ex 12 C 6
Definition of atomic weight The atomic weight of an element recorded on the periodic table is derived from the weighted average of all isotopes of that element. The most common isotope is equal to the value of the atomic weight rounded to the nearest whole number