"The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus."
Defines atomic number as the number of protons in an atom's nucleus and explains how it determines the element to which the atom belongs.
Subatomic particles: The basic constituents of atoms, including protons, neutrons, and electrons.
Atomic structure: The arrangement of subatomic particles in an atom, including the location of protons and neutrons in the nucleus and electrons in the electron cloud.
Isotopes: Atoms of the same element that have different numbers of neutrons and thus different atomic masses.
Atomic number: The number of protons in the nucleus of an atom, which determines the element and its properties.
Periodic table: A chart of the elements arranged by their atomic number and chemical properties, providing a systematic way to study atomic and chemical behavior.
Electron configuration: The arrangement of electrons in the electron cloud, which determines the chemical properties of an atom and its reactivity with other atoms.
Valence electrons: The outermost electrons in an atom, which are responsible for bonding with other atoms to form molecules and compounds.
Chemical bonding: The attractive forces that hold atoms together in molecules and compounds, including covalent, ionic, and metallic bonding.
Ionization energy: The energy required to remove an electron from an atom, which is related to the stability and reactivity of an element.
Atomic spectra: The unique patterns of light emitted or absorbed by atoms when they are excited, providing information about the electronic structure and properties of elements.
"For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (np) or the number of protons found in the nucleus of every atom of that element."
"The atomic number can be used to uniquely identify ordinary chemical elements."
"In an ordinary uncharged atom, the atomic number is also equal to the number of electrons."
"For an ordinary atom which contains protons, neutrons and electrons, the sum of the atomic number Z and the neutron number N gives the atom's atomic mass number A."
"The atomic mass of any atom, when expressed in daltons (making a quantity called the 'relative isotopic mass'), is within 1% of the whole number A."
"Atoms with the same atomic number but different neutron numbers, and hence different mass numbers, are known as isotopes."
"A little more than three-quarters of naturally occurring elements exist as a mixture of isotopes."
"The average isotopic mass of an isotopic mixture for an element (called the relative atomic mass) in a defined environment on Earth determines the element's standard atomic weight."
"Historically, it was these atomic weights of elements (in comparison to hydrogen) that were the quantities measurable by chemists in the 19th century."
"The conventional symbol Z comes from the German word Zahl 'number', which, before the modern synthesis of ideas from chemistry and physics, merely denoted an element's numerical place in the periodic table."
"Only after 1915, with the suggestion and evidence that this Z number was also the nuclear charge and a physical characteristic of atoms, did the word Atomzahl (and its English equivalent atomic number) come into common use in this context."
"The rules above do not always apply to exotic atoms which contain short-lived elementary particles other than protons, neutrons and electrons." Quote: "The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus." Quote: "For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (np) or the number of protons found in the nucleus of every atom of that element." Quote: "The atomic number can be used to uniquely identify ordinary chemical elements." Quote: "In an ordinary uncharged atom, the atomic number is also equal to the number of electrons." Quote: "For an ordinary atom which contains protons, neutrons and electrons, the sum of the atomic number Z and the neutron number N gives the atom's atomic mass number A." Quote: "The atomic mass of any atom, when expressed in daltons (making a quantity called the 'relative isotopic mass'), is within 1% of the whole number A." Quote: "Atoms with the same atomic number but different neutron numbers, and hence different mass numbers, are known as isotopes." Quote: "A little more than three-quarters of naturally occurring elements exist as a mixture of isotopes." Quote: "The average isotopic mass of an isotopic mixture for an element (called the relative atomic mass) in a defined environment on Earth determines the element's standard atomic weight." Quote: "Historically, it was these atomic weights of elements (in comparison to hydrogen) that were the quantities measurable by chemists in the 19th century." Quote: "The conventional symbol Z comes from the German word Zahl 'number', which, before the modern synthesis of ideas from chemistry and physics, merely denoted an element's numerical place in the periodic table." Quote: "Only after 1915, with the suggestion and evidence that this Z number was also the nuclear charge and a physical characteristic of atoms, did the word Atomzahl (and its English equivalent atomic number) come into common use in this context." Quote: "The rules above do not always apply to exotic atoms which contain short-lived elementary particles other than protons, neutrons and electrons."