Search

Text Color

Margin Size

Font Type

Enable Dyslexic Font

3.4: Key Terms

Last updated

Aug 6, 2024
Save as PDF
- 3.3: Chemical Nomenclature
- 3.5: Key Equations

$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$

$\newcommand{\id}{\mathrm{id}}$ $\newcommand{\Span}{\mathrm{span}}$

( \newcommand{\kernel}{\mathrm{null}\,}\) $\newcommand{\range}{\mathrm{range}\,}$

$\newcommand{\RealPart}{\mathrm{Re}}$ $\newcommand{\ImaginaryPart}{\mathrm{Im}}$

$\newcommand{\Argument}{\mathrm{Arg}}$ $\newcommand{\norm}[1]{\| #1 \|}$

$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$

$\newcommand{\Span}{\mathrm{span}}$

$\newcommand{\id}{\mathrm{id}}$

$\newcommand{\Span}{\mathrm{span}}$

$\newcommand{\kernel}{\mathrm{null}\,}$

$\newcommand{\range}{\mathrm{range}\,}$

$\newcommand{\RealPart}{\mathrm{Re}}$

$\newcommand{\ImaginaryPart}{\mathrm{Im}}$

$\newcommand{\Argument}{\mathrm{Arg}}$

$\newcommand{\norm}[1]{\| #1 \|}$

$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$

$\newcommand{\Span}{\mathrm{span}}$ $\newcommand{\AA}{\unicode[.8,0]{x212B}}$

$\newcommand{\vectorA}[1]{\vec{#1}} % arrow$

$\newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow$

$\newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vectorC}[1]{\textbf{#1}}$

$\newcommand{\vectorD}[1]{\overrightarrow{#1}}$

$\newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}}$

$\newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}}$

$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$

$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$

$\newcommand{\avec}{\mathbf a}$

$\newcommand{\bvec}{\mathbf b}$

$\newcommand{\cvec}{\mathbf c}$

$\newcommand{\dvec}{\mathbf d}$

$\newcommand{\dtil}{\widetilde{\mathbf d}}$

$\newcommand{\evec}{\mathbf e}$

$\newcommand{\fvec}{\mathbf f}$

$\newcommand{\nvec}{\mathbf n}$

$\newcommand{\pvec}{\mathbf p}$

$\newcommand{\qvec}{\mathbf q}$

$\newcommand{\svec}{\mathbf s}$

$\newcommand{\tvec}{\mathbf t}$

$\newcommand{\uvec}{\mathbf u}$

$\newcommand{\vvec}{\mathbf v}$

$\newcommand{\wvec}{\mathbf w}$

$\newcommand{\xvec}{\mathbf x}$

$\newcommand{\yvec}{\mathbf y}$

$\newcommand{\zvec}{\mathbf z}$

$\newcommand{\rvec}{\mathbf r}$

$\newcommand{\mvec}{\mathbf m}$

$\newcommand{\zerovec}{\mathbf 0}$

$\newcommand{\onevec}{\mathbf 1}$

$\newcommand{\real}{\mathbb R}$

$\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}$

$\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}$

$\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}$

$\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}$

$\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}$

$\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}$

$\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}$

$\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}$

$\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}$

$\newcommand{\laspan}[1]{\text{Span}\{#1\}}$

$\newcommand{\bcal}{\cal B}$

$\newcommand{\ccal}{\cal C}$

$\newcommand{\scal}{\cal S}$

$\newcommand{\wcal}{\cal W}$

$\newcommand{\ecal}{\cal E}$

$\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}$

$\newcommand{\gray}[1]{\color{gray}{#1}}$

$\newcommand{\lgray}[1]{\color{lightgray}{#1}}$

$\newcommand{\rank}{\operatorname{rank}}$

$\newcommand{\row}{\text{Row}}$

$\newcommand{\col}{\text{Col}}$

$\renewcommand{\row}{\text{Row}}$

$\newcommand{\nul}{\text{Nul}}$

$\newcommand{\var}{\text{Var}}$

$\newcommand{\corr}{\text{corr}}$

$\newcommand{\len}[1]{\left|#1\right|}$

$\newcommand{\bbar}{\overline{\bvec}}$

$\newcommand{\bhat}{\widehat{\bvec}}$

$\newcommand{\bperp}{\bvec^\perp}$

$\newcommand{\xhat}{\widehat{\xvec}}$

$\newcommand{\vhat}{\widehat{\vvec}}$

$\newcommand{\uhat}{\widehat{\uvec}}$

$\newcommand{\what}{\widehat{\wvec}}$

$\newcommand{\Sighat}{\widehat{\Sigma}}$

$\newcommand{\lt}{<}$

$\newcommand{\gt}{>}$

$\newcommand{\amp}{&}$

$\definecolor{fillinmathshade}{gray}{0.9}$

Example and Directions
Words (or words that have the same definition)	The definition is case sensitive	(Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages]	(Optional) Caption for Image	(Optional) External or Internal Link	(Optional) Source for Definition
(Eg. "Genetic, Hereditary, DNA ...")	(Eg. "Relating to genes or heredity")		The infamous double helix	https://bio.libretexts.org/	CC-BY-SA; Delmar Larsen

Glossary Entries
Word(s)	Definition	Image	Caption	Link	Source
actinide	inner transition metal in the bottom of the bottom two rows of the periodic table
alkali metal	element in group 1
alkaline earth metal	element in group 2
alpha particle (α particle)	positively charged particle consisting of two protons and two neutrons
anion	negatively charged atom or molecule (contains more electrons than protons)
atomic mass	average mass of atoms of an element, expressed in amu
atomic mass unit (amu)	(also, unified atomic mass unit, u, or Dalton, Da) unit of mass equal to of the mass of a ¹²C atom
atomic number (Z)	number of protons in the nucleus of an atom
binary acid	compound that contains hydrogen and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H⁺ ions when dissolved in water)
binary compound	compound containing two different elements.
cation	positively charged atom or molecule (contains fewer electrons than protons)
chalcogen	element in group 16
chemical symbol	one-, two-, or three-letter abbreviation used to represent an element or its atoms
covalent bond	attractive force between the nuclei of a molecule’s atoms and pairs of electrons between the atoms
covalent compound	(also, molecular compound) composed of molecules formed by atoms of two or more different elements
Dalton (Da)	alternative unit equivalent to the atomic mass unit
Dalton’s atomic theory	set of postulates that established the fundamental properties of atoms
electron	negatively charged, subatomic particle of relatively low mass located outside the nucleus
empirical formula	formula showing the composition of a compound given as the simplest whole-number ratio of atoms
fundamental unit of charge	(also called the elementary charge) equals the magnitude of the charge of an electron (e) with e = 1.602 10⁻¹⁹ C
group	vertical column of the periodic table
halogen	element in group 17
hydrate	compound containing one or more water molecules bound within its crystals
inert gas	(also, noble gas) element in group 18
inner transition metal	(also, lanthanide or actinide) element in the bottom two rows; if in the first row, also called lanthanide, or if in the second row, also called actinide
ion	electrically charged atom or molecule (contains unequal numbers of protons and electrons)
ionic bond	electrostatic forces of attraction between the oppositely charged ions of an ionic compound
ionic compound	compound composed of cations and anions combined in ratios, yielding an electrically neutral substance
isomers	compounds with the same chemical formula but different structures
isotopes	atoms that contain the same number of protons but different numbers of neutrons
lanthanide	inner transition metal in the top of the bottom two rows of the periodic table
law of constant composition	(also, law of definite proportions) all samples of a pure compound contain the same elements in the same proportions by mass
law of definite proportions	(also, law of constant composition) all samples of a pure compound contain the same elements in the same proportions by mass
law of multiple proportions	when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small whole numbers
main-group element	(also, representative element) element in groups 1, 2, and 13–18
mass number (A)	sum of the numbers of neutrons and protons in the nucleus of an atom
metal	element that is shiny, malleable, good conductor of heat and electricity
metalloid	element that conducts heat and electricity moderately well, and possesses some properties of metals and some properties of nonmetals
molecular compound	(also, covalent compound) composed of molecules formed by atoms of two or more different elements
molecular formula	formula indicating the composition of a molecule of a compound and giving the actual number of atoms of each element in a molecule of the compound.
monatomic ion	ion composed of a single atom
neutron	uncharged, subatomic particle located in the nucleus
noble gas	(also, inert gas) element in group 18
nomenclature	system of rules for naming objects of interest
nonmetal	element that appears dull, poor conductor of heat and electricity
nucleus	massive, positively charged center of an atom made up of protons and neutrons
oxyacid	compound that contains hydrogen, oxygen, and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H⁺ ions when dissolved in water)
oxyanion	polyatomic anion composed of a central atom bonded to oxygen atoms
period	(also, series) horizontal row of the periodic table
periodic law	properties of the elements are periodic function of their atomic numbers.
periodic table	table of the elements that places elements with similar chemical properties close together
pnictogen	element in group 15
polyatomic ion	ion composed of more than one atom
proton	positively charged, subatomic particle located in the nucleus
representative element	(also, main-group element) element in columns 1, 2, and 12–18
series	(also, period) horizontal row of the period table
spatial isomers	compounds in which the relative orientations of the atoms in space differ
structural formula	shows the atoms in a molecule and how they are connected
structural isomer	one of two substances that have the same molecular formula but different physical and chemical properties because their atoms are bonded differently
transition metal	element in groups 3–12 (more strictly defined, 3–11; see chapter on transition metals and coordination chemistry)
unified atomic mass unit (u)	alternative unit equivalent to the atomic mass unit

actinide | inner transition metal in the bottom of the bottom two rows of the periodic table

alkali metal | element in group 1

alkaline earth metal | element in group 2

alpha particle (α particle) | positively charged particle consisting of two protons and two neutrons

anion | negatively charged atom or molecule (contains more electrons than protons)

atomic mass | average mass of atoms of an element, expressed in amu

atomic mass unit (amu) | (also, unified atomic mass unit, u, or Dalton, Da) unit of mass equal to of the mass of a ¹²C atom

atomic number (Z) | number of protons in the nucleus of an atom

binary acid | compound that contains hydrogen and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H⁺ ions when dissolved in water)

binary compound | compound containing two different elements.

cation | positively charged atom or molecule (contains fewer electrons than protons)

chalcogen | element in group 16

chemical symbol | one-, two-, or three-letter abbreviation used to represent an element or its atoms

covalent bond | attractive force between the nuclei of a molecule’s atoms and pairs of electrons between the atoms

covalent compound | (also, molecular compound) composed of molecules formed by atoms of two or more different elements

Dalton (Da) | alternative unit equivalent to the atomic mass unit

Dalton’s atomic theory | set of postulates that established the fundamental properties of atoms

electron | negatively charged, subatomic particle of relatively low mass located outside the nucleus

empirical formula | formula showing the composition of a compound given as the simplest whole-number ratio of atoms

fundamental unit of charge | (also called the elementary charge) equals the magnitude of the charge of an electron (e) with e = 1.602 10⁻¹⁹ C

group | vertical column of the periodic table

halogen | element in group 17

hydrate | compound containing one or more water molecules bound within its crystals

inert gas | (also, noble gas) element in group 18

inner transition metal | (also, lanthanide or actinide) element in the bottom two rows; if in the first row, also called lanthanide, or if in the second row, also called actinide

ion | electrically charged atom or molecule (contains unequal numbers of protons and electrons)

ionic bond | electrostatic forces of attraction between the oppositely charged ions of an ionic compound

ionic compound | compound composed of cations and anions combined in ratios, yielding an electrically neutral substance

isomers | compounds with the same chemical formula but different structures

isotopes | atoms that contain the same number of protons but different numbers of neutrons

lanthanide | inner transition metal in the top of the bottom two rows of the periodic table

law of constant composition | (also, law of definite proportions) all samples of a pure compound contain the same elements in the same proportions by mass

law of definite proportions | (also, law of constant composition) all samples of a pure compound contain the same elements in the same proportions by mass

law of multiple proportions | when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small whole numbers

main-group element | (also, representative element) element in groups 1, 2, and 13–18

mass number (A) | sum of the numbers of neutrons and protons in the nucleus of an atom

metal | element that is shiny, malleable, good conductor of heat and electricity

metalloid | element that conducts heat and electricity moderately well, and possesses some properties of metals and some properties of nonmetals

molecular compound | (also, covalent compound) composed of molecules formed by atoms of two or more different elements

molecular formula | formula indicating the composition of a molecule of a compound and giving the actual number of atoms of each element in a molecule of the compound.

monatomic ion | ion composed of a single atom

neutron | uncharged, subatomic particle located in the nucleus

noble gas | (also, inert gas) element in group 18

nomenclature | system of rules for naming objects of interest

nonmetal | element that appears dull, poor conductor of heat and electricity

nucleus | massive, positively charged center of an atom made up of protons and neutrons

oxyacid | compound that contains hydrogen, oxygen, and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H⁺ ions when dissolved in water)

oxyanion | polyatomic anion composed of a central atom bonded to oxygen atoms

period | (also, series) horizontal row of the periodic table

periodic law | properties of the elements are periodic function of their atomic numbers.

periodic table | table of the elements that places elements with similar chemical properties close together

pnictogen | element in group 15

polyatomic ion | ion composed of more than one atom

proton | positively charged, subatomic particle located in the nucleus

representative element | (also, main-group element) element in columns 1, 2, and 12–18

series | (also, period) horizontal row of the period table

spatial isomers | compounds in which the relative orientations of the atoms in space differ

structural formula | shows the atoms in a molecule and how they are connected

structural isomer | one of two substances that have the same molecular formula but different physical and chemical properties because their atoms are bonded differently

transition metal | element in groups 3–12 (more strictly defined, 3–11; see chapter on transition metals and coordination chemistry)

unified atomic mass unit (u) | alternative unit equivalent to the atomic mass unit

Support Center

How can we help?