Chapter 1 Definitions Flashcards
Atom
The smallest unit of matter, consisting of a nucleus (protons and neutrons) surrounded by electrons.
Electron
A negatively charged subatomic particle found in the electron cloud around the nucleus of an atom.
Proton
A positively charged subatomic particle found in the nucleus of an atom.
Neutron
A neutral subatomic particle found in the nucleus of an atom, with a mass roughly equal to that of a proton.
Electron Transition
The movement of an electron between different energy levels or orbitals within an atom
Emission Spectrum
A spectrum of emitted light when electrons in an atom return to lower energy states, emitting photons of specific wavelengths.
Continuous Spectrum
A spectrum that shows a continuous range of wavelengths of light, without gaps or lines.
Energy Level
A specific region around the nucleus where electrons are likely to be found, corresponding to different energy states.
Valence Shell
The outermost electron shell of an atom, involved in chemical bonding.
Valence Electron
An electron in the outermost shell of an atom, which participates in chemical reactions.
Atomic Number:
The number of protons in the nucleus of an atom, determining the element’s identity.
Mass Number
The sum of protons and neutrons in the nucleus of an atom.
Stable Octet
A stable arrangement of eight electrons in the valence shell of an atom, typically associated with noble gases.
Ion
An atom or molecule that has gained or lost one or more electrons, resulting in a charged particle.
Cation
A positively charged ion, formed when an atom loses electrons.
Anion
A negatively charged ion, formed when an atom gains electrons.
Multivalent
Describes an element that can form ions with different charges, such as transition metals.
Polyatomic Ion
An ion made up of two or more atoms that are covalently bonded and carry a charge.
Isotope
Atoms of the same element with the same number of protons but different numbers of neutrons.
Isotopic Abundance
The relative percentage of each isotope of an element in a sample.
Radioactive Decay
The process by which an unstable atomic nucleus loses energy by emitting radiation.
Nuclear Radiation
Particles or electromagnetic radiation emitted from the nucleus of a radioactive atom.
Alpha Particle
A particle consisting of 2 protons and 2 neutrons, emitted during radioactive decay.
Beta Particle
A high-energy electron or positron emitted during radioactive decay.
Gamma Ray
High-energy electromagnetic radiation emitted from the nucleus of a radioactive atom.
Radioisotope
An isotope of an element that is unstable and undergoes radioactive decay.
Average Atomic Mass:
The weighted average mass of an element’s isotopes, based on their relative abundance.
Group
A vertical column in the periodic table, containing elements with similar chemical properties.
Period:
A horizontal row in the periodic table, indicating elements with the same number of electron shells.
Periodic Law
The law stating that the chemical properties of elements are periodic functions of their atomic numbers.
Lewis Symbol
A representation of an element’s valence electrons as dots around the element’s symbol.
Atomic Radius
The distance from the nucleus of an atom to the outermost electron shell.
Effective Nuclear Charge
The net positive charge experienced by an electron, considering both the full nuclear charge and electron shielding.
Ionization Energy
The energy required to remove an electron from an atom or ion in the gas phase.
Electron Affinity
The energy change that occurs when an electron is added to a neutral atom to form an anion.
Successive Ionization Energy
The energy required to remove an electron from a positively charged ion, after one or more electrons have already been removed.
Isoelectronic
Describes two atoms, ions, or molecules that have the same electron configuration.
