Understanding Atomic Mass and Isotopes

Atomic Mass

The weighted average of the atomic masses of the naturally occurring isotopes of an element.

Average Atomic Mass Calculation

Calculated as the sum of the products of the isotopic mass of each isotope and its natural abundance percentage.

Chlorine Atomic Mass Calculation

35.050(0.7578) + 36.870(0.2422) = 26.56089 + 8.9400860 = 35.49

Proton Total Mass in Gold-198

Approximately 79 atomic mass units

Neutron Total Mass in Gold-198

Approximately 119 atomic mass units

Particle Mass Comparison to Proton

An alpha particle has a mass approximately the same as a proton.

Carbon Atom Mass Number

The mass number is 14.

Total Neutrons in Atom

There are 31 neutrons in an atom of the element.

Isotopes Definition

Isotopes of an element have the same number of protons but a different number of neutrons.

Different Chromium Isotope Notation

52^24Cr

Gallium Atomic Mass Calculation

68.9260(60.11) + 70.925(39.89) = 69.71

Oxygen-17 Nucleus Charge

The charge is -2.

Isotope Percent Abundance Calculation

63(0.78098) + 65(0.2597) = 24.3 amu

Neutral Cadmium Atom Electrons

48 electrons

Isotopes of Potassium Explanation

K-37 and K-42 are isotopes due to having the same number of protons but different numbers of neutrons.

Electrically Neutral Potassium Atoms Explanation

All atoms of potassium are electrically neutral due to having an equal number of protons and electrons.