Calculate the fundamental properties of an atom, including its mass number and electronic configuration.
Nuclear Composition
Calculation Results
Enter the number of protons and neutrons to see the atom's properties
About this calculator
Overview
An atom is the smallest unit of an element that retains its chemical properties. It consists of a nucleus containing protons and neutrons, surrounded by electrons.
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Pro Tips
The number of protons (atomic number) defines the element's identity.
In a neutral atom, the number of electrons equals the number of protons.
The number of neutrons plus the number of protons equals the mass number.
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Fun Facts
"The term 'atom' comes from the Greek word 'atomos', meaning 'indivisible', coined by philosopher Democritus in the 5th century BCE."
"Atoms are 99.9% empty space - if an atom were the size of a sports arena, the nucleus would be about the size of a pea."
"A human hair is about 1 million carbon atoms wide, and your body contains about 7 octillion atoms."
"There are 118 different types of atoms, corresponding to the elements on the periodic table."
"The strong nuclear force binding protons and neutrons is 1,038 times more powerful than gravity, though it only works at very close range."
"Electrons move at about 2,200 kilometers per second, less than 1% the speed of light, but fast enough to circle Earth in 18 seconds."
"Most of the mass of an atom is in the nucleus (protons and neutrons); electrons contribute almost no mass."
"If you removed all the empty space from the atoms that make up all humans on Earth, our entire population would fit into a sugar cube!"
"Quarks are the smaller particles that make up protons and neutrons. Protons are 2 up quarks + 1 down quark; neutrons are 1 up + 2 down."
