Atomic Structure Concepts
14 concepts · Grades 6-8, 9-12 · 20 prerequisite connections
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Atomic Structure concepts have 10 connections to other families.
All Atomic Structure Concepts
Atom
The smallest unit of an element that retains the chemical properties of that element.
Element
A pure substance consisting entirely of atoms with the same number of protons (same atomic number), which cannot be broken down into simpler substances by chemical means.
Proton
A positively charged subatomic particle found in the nucleus of every atom, with a charge of $+1$ and a mass of approximately 1 atomic mass unit (amu).
Neutron
A neutral subatomic particle found in the nucleus of an atom that has no electric charge but contributes to the atom's mass.
Electron
A negatively charged subatomic particle with negligible mass that occupies energy levels (shells) outside the nucleus.
Atomic Number
The number of protons in an atom's nucleus, which uniquely identifies the element and determines its position in the periodic table.
Mass Number
The total count of protons and neutrons (collectively called nucleons) in an atom's nucleus, always a whole number, used to identify specific isotopes of an element.
Isotope
Atoms of the same element that have the same number of protons but different numbers of neutrons, giving them different mass numbers.
Electron Shell
A discrete energy level surrounding the atomic nucleus where electrons reside, with each shell ($n = 1, 2, 3, ...$) holding a maximum of $2n^2$ electrons.
Valence Electron
An electron residing in the outermost (highest-energy) occupied shell of an atom, available for participation in chemical bonding through sharing, gaining, or losing.
Ion
An atom or group of atoms that has gained or lost one or more electrons, resulting in a net positive charge (cation) or a net negative charge (anion).
Electron Configuration
The specific arrangement of electrons in an atom's orbitals, described using subshell notation that indicates the energy level, sublevel type, and number of electrons in each subshell.
Radioactivity
The spontaneous emission of radiation (alpha particles, beta particles, or gamma rays) from an unstable atomic nucleus as it transforms into a more stable configuration.
Half-Life
Half-life is the time required for half of the radioactive nuclei in a sample to decay.