electron
Negatively charged subatomic particle
A very small particle with a negative electric charge.
an electron; electrons
- An electron has a negative electric charge.
- When an atom gains an extra electron, it becomes negatively charged.
- Scientists measured the electron’s energy in the experiment.
- An electron is very small.
- Electrons have a negative charge.
Electron in an atom or molecule
An electron that is part of an atom or molecule.
an electron in [an atom/molecule]; valence electrons
- Sodium has one valence electron that it readily loses.
- The two atoms share a pair of electrons in a covalent bond.
- Removing an electron from the atom requires energy.
- This atom has two electrons in its outer shell.
Charge carrier in electric current
A moving electron that carries electricity in a wire or device.
electrons flow through [a wire/material]; electron flow
- In a metal wire, electrons move through the lattice when a voltage is applied.
- The device works by controlling the flow of electrons through a thin channel.
- Higher electron mobility allows faster switching in some semiconductors.
- Electrons can flow through a wire.
- Base: electron
- Plural: electrons
electron beam
1Stream of electrons
A thin stream of electrons used in machines and experiments.
- The electron beam was focused onto the surface to create a detailed image.
- Electron-beam lithography can produce extremely fine patterns.
- The operator adjusted the electron beam to improve resolution.
electron cloud
1Region where electrons are likely
The space around the nucleus where electrons are likely to be.
- The electron cloud model explains why electrons don’t follow neat circular orbits.
- In this diagram, the shaded area represents the electron cloud.
- Chemical bonds form when electron clouds overlap.
electron configuration
1Arrangement of electrons in atom
How electrons are arranged in an atom.
- Chlorine’s electron configuration helps explain its tendency to form ions.
- The table lists the electron configuration for each element.
- Ions have different electron configurations from their neutral atoms.
electron density
1Amount of electron charge in space
A way to describe where electrons are concentrated.
- The double bond has higher electron density than a single bond.
- The map shows electron density around the atoms in the crystal.
- Adding an electron-withdrawing group reduces electron density in the ring.
electron microscope
1Microscope using electron beams
A powerful microscope that uses electrons to make an image.
- The researchers examined the virus under an electron microscope.
- Electron microscopes can reveal structures far smaller than a typical light microscope.
- The sample had to be prepared carefully before electron microscope imaging.
electron shell
1Energy level around nucleus
A layer (energy level) where electrons can be in an atom.
- Atoms are most reactive when their outer electron shell is not full.
- The first electron shell can hold a maximum of two electrons.
- Electrons in inner shells are held more tightly by the nucleus.
electron transfer
1Movement of electrons between atoms
When an electron moves from one atom or molecule to another.
- Rusting involves electron transfer from iron to oxygen.
- Electron transfer is central to many reactions in batteries.
- The protein complex enables electron transfer in photosynthesis.
free electron
1Electron not bound to atom
An electron that can move freely, not attached to one atom.
- Metals conduct well because they have many free electrons.
- In a plasma, free electrons and ions move independently.
- The model treats the metal as a sea of free electrons.