Isotopes

Isotopes

An Isotope is an atom with a different number of neutrons than the number of protons

Symbols:  11/5 B (Boron-11)

• top number (11)- mass number
• bottom number (5)- atomic number

Example; Carbon will always have 6 protons, but the number of neutrons can change

• Carbon-12 (6 protons, 6 neutrons)
• Carbon-13 (6 protons, 7 neutrons)
• Carbon-14 (6 protons, 8 neutrons)

Average atomic mass is the weighted average of the mass numbers of the isotopes of an element. This is what is listed on the periodic table.
   eg. Carbon’s average atomic mass is 12.01