Scientists Say: Electron

Electrons are negatively charged particles that orbit the nucleus, or center, of an atom

an illustration of an atom shows a nucleus composed of red and white dots to represent protons and neutrons, surrounded by blue dots that represent electrons

Electrons are negatively charged particles that swarm around the nucleus of an atom. In this model of an atom, the electrons are represented by blue dots. The red and white dots are particles in the nucleus called protons and neutrons.


Electron (noun, “Ee-LEK-trahn”) 

This is one of the three types of particles that make up an atom. The other two are protons and neutrons. Protons and neutrons form the center, or nucleus, of an atom. Electrons exist in a surrounding cloud. They swarm around the center of the atom. That’s because electrons have negative electric charge. That makes them attracted to the positively charged protons in the nucleus. Normally, atoms have the same number of electrons as protons. So the atoms are electrically neutral.

Unlike protons and neutrons, electrons don’t contain smaller particles. That is, they are fundamental particles. Each electron is extremely small. Its mass is only about 1/1,800 the mass of a proton or neutron. Still, electrons play an important role in how atoms behave. Atoms of different elements hold their electrons in different arrangements around the nucleus. That arrangement gives each element its distinct properties. For instance, it determines how well an element conducts electricity. It also determines the temperature at which the element boils. And, that arrangement governs how likely atoms are to share electrons with each other. When atoms share electrons, they link together and form molecules.

In a sentence

In chemical reactions called redox reactions, one atom steals electrons from another.

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Maria Temming is the Assistant Managing Editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.

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