The weighted average of the masses of the isotopes of an element
Atomic mass
The total number of protons and neutrons in the nucleus of an atom
Mass number
1/12th the mass of a carbon atom having 6 protons and 6 neutrons
Atomic mass unit
Atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom
Isotope
The number of protons in the nucleus of an element
Atomic number
A negatively charged subatomic particle
Electron
The smallest particle of an element that retains the properties of that element
Atom
The central part of an atom, containing protons & neutrons
Nucleus
A subatomic particle with no charge
Neutron
A positively charged subatomic particle
Proton
All atoms are
Neutral, with the number of protons equaling the number of electrons
What does the number 84 in the name krypton-84 represent
The mass number
Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses of the atoms?
The actual masses of atoms are very small and difficult to work with.
The atomic number of an element is the total number of which particles in the nucleus?
Protons
All atoms of the same element have the same
Number of protons
The sum of protons and neutrons in an atom equals the
Mass number
An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are
76 protons & 76 electrons
Isotopes of the same element have different
Mass numbers
How many protons, electrons & neutrons does an atom with atomic number 50 and mass number 125 contain?
50 protons, 50 electrons & 75 neutrons
What unit is used to measure weighted average atomic mass?
amu
What is the relative mass of an electron
1/1840 the mass of a hydrogen atom
The atomic mass of an element is the
Weighted average of the masses of the isotopes of the element
How is the number of neutrons in the nucleus of an atom calculated?
Subtract the number of protons from the mass number