Q:

# What is the mass of the helium nucleus?

A:

The mass of the helium nucleus is 6.64 x 10^-27 kilograms. The mass is calculated by adding together the mass of two protons, each of which has a mass of 1.67 x 10^-27 kilograms and two neutrons, which each have a mass of 1.67 x 10^-27 kilograms.

## Keep Learning

The mass of a helium nucleus can also be expressed as "4 u," which stands for atomic mass units, or 3.72 GeV/c^2 gigaelectronvolts over the speed of light squared. The helium nucleus has a mass that is the same as that of an alpha particle. The number is used in the calculation for the mass defect of the helium nucleus that is needed for the equation E = mc^2.

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## Related Questions

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The atomic mass of an element is determined by the number of subatomic particles in the nucleus. The subatomic particles contained within a nucleus are called protons and neutrons.

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When a nucleus emits a positron, its atomic number is lowered by one but its mass number stays the same. Positron emission is also known as positive beta decay and involves the decay of a proton into a neutron.

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An atomic mass unit is defined as being equal to 1/12th the mass of an atom of carbon-12 and is approximately 1.66x10-27 kilograms. The atomic mass unit is the unit of measure used when calculating the atomic mass of an element.