Electron A negatively charged particle that

Electron a negatively charged particle that moves around the nucleus of an atom. (2.5)... 

Q Review Vocabulary electron a negatively charged particle that exists in an electron cloud around an atom s nucleus... 

Electron—a negatively charged particle that orbits the nucleus of an atom. 

All materials are composed of atoms, which in turn consist of a nucleus and a number of shells of planetary electrons. Electrons are negatively charged particles that are extremely small and essentially weightless. An atom consists mostly of empty space. This aspect of atomic structure was anticipated by Galileo. An atom is electrically neutral and for each planetary electron there is a positively charged particle (proton) in the nucleus. The protons have about 2,000 times the mass of an electron. The weight of the atom is due primarily to the protons and neutrons in the nucleus. A neutron is an uncharged proton (or proton + electron). 

The electron is a negatively charged particle that moves in an orbital around the nucleus and so consequently has orbital angular momentum. It also spins about its own axis and therefore has a spin angular momentum given by... 

Experiments like those described in Figures 14-3 to 14-6 establish that the electron is a negatively charged particle and that it is present in all substances. Further confirmation of the particulate nature of electricity comes from experiments that were conducted by an American physi-... 

In 1897, Dalton s idea of an indivisible atom was shattered with a startling announcement. A British scientist, Joseph John Thomson, had discovered the existence of a negatively charged particle with mass less than that of a hydrogen atom. This particle was, of course, the electron. 

Electron A negatively charged subatomic particle that constitutes an insignificant amount of the mass of an atom. 

Electron A negatively charged subatomic particle with almost no mass that can be found outside of the nucleus of an atom of an element. 

Electron The negatively charged particle of very small mass (1 / 2000 that of a proton) that orbits around the nucleus in the atom. 

Corpuscularian One who believed in matter composed of corpuscles. Electron One of the three basic subatomic components of all elements. It is a negatively charged particle with virtually no mass that orbits the nucleus of an atom. 

The electrons are negatively charged particles. The mass of an electron is about 2000 times smaller than that of an proton or neutron at 0.00055 amu. Electrons circle so fast that it cannot be determined where electrons are at any point in time, rather, we talk about the probability of finding an electron at a point in space relative to a nucleus at any point in time. The image depicts the old Bohr model of the atom, in which the electrons inhabit discrete "orbitals" around the nucleus much like planets orbit the sun. This model is outdated. Current models of the atomic structure hold that electrons occupy fuzzy clouds around the nucleus of specific shapes, some spherical, some dumbbell shaped, some with even more complex shapes. Even though the simpler Bohr model of atomic structure has been superseded, we still refer to these electron clouds as "orbitals". The number of electrons and the nature of the orbitals they occupy basically determines the chemical properties and reactivity of all atoms and molecules. 

The first studies of the ionosphere using radiowave techniques demonstrated that electrons are nearly absent below 65 or 70 km during the day and 75 or 80 km at night. However, electrical neutrality requires a balance between charged particles. The observation of positive ions implies that equal quantities of a negatively charged particle must be present. 

The path of discovery is often winding and unpredictable. Basic research into the nature of electricity eventually led to the discovery of electrons, negatively charged particles that are part of all atoms. Soon thereafter, other experiments revealed that the atom has a nucleus—a tiny, central core of mass and positive charge. In this section, we examine some key experiments that led to our current model of the atom. 

By the 1930s, however, it was clear that atoms were made up of even smaller particles—protons, neutrons, and electrons, then considered to be the fundamental particles of matter. (A proton is a positively charged particle that weighs about one atomic mass unit [1.0073 AMU] a neutron has about the same mass [1.0087 AMU] but no charge and an electron has a much smaller mass [0.0005 AMU] and a negative charge.) Protons and neutrons make up the tiny nucleus of an atom, while electrons exist outside the atomic nucleus in discrete energy levels within an electron cloud. ... 

The addition of an electron to a neutral atom is described quantitatively by its electron affinity. This process produces a negatively charged particle called an anion, whose chemical properties bear no relationship to those of the neutral atom. In adding an electron to a neutral atom the principal force which operates is the attractive force of the positive nucleus. The attractive force of the positive nucleus decreases as the periods increase, because as additional electron shells are added to the atom, the outer electrons become more insulated from the nucleus by the intervening electron shells. It is easier to add an electron to the valence shell of fluorine (Period 2) than to that of chlorine (Period 3), and easier yet to add an electron to the valence shell of chlorine (Period 3) than to that of bromine (Period 4). The ease of forming anions within Group VII of the Periodic Table is F > Cl > Br > I. 

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