Atom's structure

What Is an Electron? Mass, Charge and Characteristics

What is an electron? Mass, charge and characteristics

An electron is a negatively charged stable elementary charge. Along with neutrons and protons, it is one of the three sub-particles that make up an atom. For this reason, it can also be defined as a subatomic particle that belongs to the group of leptons.

They can appear in a free state (without being attached to any atom) or attached to the nucleus of an atom using chemical bonding.

The Penning trap is often used to make precise measurements of this type of particle.

Electrons exist in atoms in spherical shells of various radius. These spherical layers represent energy levels. The larger the spherical shell, the greater the energy contained in this elementary particle.

Electric fields are created by electric charges, or by time-varying magnetic fields.

Its antiparticle is the positron. Electrons and positrons have the same amount of mass, spin, and charge as the electron. The difference is that charges have different sign.

Quantum mechanical properties of the electron include a spin of a half-integer value. Spin is intrinsic angular momentum associated with elementary particles. Spin is intrinsic to the particle itself, so that, it is not associated with any rotating internal parts of elementary particles.

Electric Energy

In electrical conductors, current flows are the electrons of atoms that circulate individually from one atom to another in the direction of the negative pole to the positive pole of the electrical conductor. It is what we call electrical energy or electricity.

Although they are usually part of atoms, there are electrons that form beams in a vacuum or move independently through matter.

In semiconductor materials, electric current is also produced by the movement of these sub-particles.

Electron Electric Charge

The charge of an electron is 1.60 x 10-19 C. Its charge is a fundamental physical constant.

What is an electron? Mass, charge and characteristicsThe amount of electric charge is not measured in terms of the charge of a single sub particle because it is extremely small. Instead, the Coulomb is used, with symbol C. The Coulomb is the standard unit of the quantity of electric charge. A Coulomb represents about 6.24 x 1018 electrons.

The charge of a single one of these sub-particles is considered as the unit of elementary electric charge. It is assigned negative polarity, so we say it has a negative electric charge.

From a physical point of view, protons and electrons have the same elemental charge but with opposite sign. The proton is positively charged.

Atoms are composed of protons, neutrons, and electrons. As neutrons are electrically neutral, the number of electrons must be the same as the number of protons.

How Was It Determined? Millikan Oil Drop Experiment

The purpose of the Robert Millikan and Harvey Fletcher oil drop experiment was to determine the charge of a single electron. They did this by keeping a small drop of oil floating between two condenser plates.

They found that the measured values ​​were always a multiple of the same load. They interpreted this as a charge on a single electron: 1,602 × 10−19 Coulomb.

In 1923 Millikan won the Nobel Prize for Physics.

What Is a Magnetic Field and How Is It Created?

A magnetic field describes a volume of space where there is a change in energy.

When an electrical charge is in motion produces a magnetic field. The orbiting and spinning of the atomic nucleus generates a magnetic field. It is the same case observed in an electric current where a magnetic field is created because of the electron moving through a wire.

Electron Mass

Its mass is approximately 9.11 x 10-31 kg. It is a fundamental physical constant.

Electrons moving at an appreciable fraction of the speed of light have a higher mass due to relativistic effects. That is, the mass of the electron increases with speed, according to Albert Einstein's predictions.

The electron mass is practically insignificant compared with the mass of a proton or a neutron.

Atomic Electronic Transition

This transition is a change of an electron from one energy level to another within an atom 1 or artificial atom.  It appears as discontinuous when the electron "jumps" from one energy level to another in a few nanoseconds or less.

These transitions cause the emission or absorption of electromagnetic radiation in the form of quantized units called photons.

The greater the energy separation of the states between which it jumps, the shorter the wavelength of the emitted photon will be.

History and Discovery

This sub-particle was the first elementary particle discovered.

In 1895 Jean Perrin, analyzing the electrical charge of the so-called cathode rays, showed that they carried a negative charge using cathode ray tubes.

Joseph John Thomson managed to determine the specific charge of the particles. In 1906 Thomson won the Nobel Prize for Physics.

Millikan took advantage of Thomson's work to carry out the oil drop experiment. In this experiment, he was able to measure the load and the mass

The production of free electrons has led to the development of electronics.

Among the history, it has been a lot of atomic theories. However, the final model accepted is the standard model of Bhor.


Published: October 27, 2016
Last review: June 11, 2020