Isotopes

• Isotopes are atoms with different masses but the same number of protons.
• Atomic Mass, A, mass of the element
• Atomic #, Z, number of protons in the element.
• X is the symbol for the element
• To find the ATOMIC MASS:

  # of protons + # of neutrons
• Isotopes = Two or more atoms that have the same # of protons and different # of neutrons for an element.
• For example: Carbon has three isotopes - ALL having 3 PROTONS, meaning the ATOMIC # (Z) must be the SAME; They have DIFFERENT number of neutrons, that can be ADDED up to the ATOMIC MASS (A).
• amu = unit of mass for elements and compounds
• Carbon-12, for example, is 12 amu.
• Neutral atoms = # of PROTONS = # of ELECTRONS