Completar frases Take Away Ideas: Part 4Versión en línea Review Take Away Ideas: Part 4 por Shari Cayer 1 number total together overall Name electrons NOT contributions not bottom protons average nucleus atomic Isotope small not whole add NOT mass particular average fraction mass add The mass number of an atom is equal to the number of and neutrons found in the of a atom . The mass number of a particular atom is the same as the average of an element . The mass number is found on the Periodic Table . In order to determine the mass number of a particular atom , you need to the number of protons and neutrons together and since you can't have a of a proton or neutron , the sum will always be a number . The number on the of each box on the Periodic Table is known as the atomic mass . This is an for all of the atoms of a particular element . If you need to determine the mass number of a particular atom , do NOT look on the Periodic Table for this number , since it is found there . Simply the number of protons and neutrons in a particular atom . The is a quick way of representing the name or symbol of the element followed by the . Adding or removing from the electron cloud does affect mass of an atom since they are too to make a significant to the mass of the atom .