AS 1.2.1-7: Atomic Structure and Mass Spectrometry Flashcards
Atomic Number
The number of protons in the nucleus of an atom.
Mass Number
The total number of protons and neutrons in (the nucleus of) an atom.
Isotopes
Atoms of the same element which have the same atomic number but different mass numbers. [They have the same number of protons but different numbers of neutrons.]
Relative Isotopic Mass
The mass of an atom of an isotope of an element relative to one-twelfth of the mass of an atom of carbon-12.
Relative Molecular Mass
The average (weighted mean) mass of an atom of an element relative to one-twelfth of the mass of an atom of carbon-12.
Relative Formula Mass
The average (weighted mean) mass of a formula unit relative to one-twelfth of the mass of an atom of carbon-12.