| Term | Definition |
|---|---|
| bond dipole | The separation of partial positive and negative charges in a polar bond; greater electronegativity differences lead to greater bond dipoles. |
| covalent bond | A chemical bond typically formed between two nonmetals where valence electrons are shared between atoms. |
| delocalized electrons | Valence electrons in a metallic solid that are not associated with any individual atom but are distributed throughout the structure. |
| electronegativity | A measure of an atom's ability to attract valence electrons in a chemical bond; increases across a period and decreases down a group in the periodic table. |
| ionic bond | A chemical bond typically formed between a metal and nonmetal where electrons are transferred from one atom to another. |
| ionic character | The degree to which a bond exhibits properties of an ionic bond; all polar bonds possess some ionic character. |
| metallic solid | A solid composed of metal atoms where valence electrons are delocalized and not associated with any individual atom. |
| nonpolar covalent bond | A covalent bond between atoms of similar electronegativity where valence electrons are shared relatively equally. |
| partial negative charge | The negative charge that develops on the more electronegative atom in a polar covalent bond. |
| polar covalent bond | A covalent bond between atoms of unequal electronegativity where valence electrons are shared unequally, resulting in partial charges on the atoms. |
| valence electrons | Electrons in the outermost shell of an atom that participate in bonding and determine many properties of substances. |
| Term | Definition |
|---|---|
| anion | A negatively charged ion formed when an atom gains one or more electrons. |
| bond energy | The average energy required to break a chemical bond between two atoms. |
| bond length | The distance between the nuclei of two bonded atoms, which is affected by bond order and atomic radius. |
| bond order | The number of electron pairs shared between two atoms in a chemical bond, which affects bond energy and bond length. |
| cation | A positively charged ion formed when an atom loses one or more electrons. |
| Coulomb's law | The principle that the electrostatic force between charged particles is proportional to the product of their charges and inversely proportional to the square of the distance between them. |
| covalent bond | A chemical bond typically formed between two nonmetals where valence electrons are shared between atoms. |
| equilibrium bond length | The separation between atoms at which the potential energy is at its lowest point, representing the most stable bond distance. |
| internuclear distance | The distance between the nuclei of two atoms, which influences the strength of the interaction between them. |
| ionic interaction | The electrostatic attraction between cations and anions, whose strength depends on the charges of the ions and the distance between them. |
| potential energy | The stored energy in chemical bonds and molecular structures that can be released or absorbed during a reaction. |
| Term | Definition |
|---|---|
| anion | A negatively charged ion formed when an atom gains one or more electrons. |
| attractive forces | Electrostatic forces between oppositely charged ions that hold them together in an ionic solid. |
| cation | A positively charged ion formed when an atom loses one or more electrons. |
| Coulomb's law | The principle that the electrostatic force between charged particles is proportional to the product of their charges and inversely proportional to the square of the distance between them. |
| ionic crystal | A solid structure in which cations and anions are arranged in a repeating three-dimensional pattern. |
| ionic solid | A crystalline compound composed of cations and anions held together by electrostatic forces. |
| particulate model | A representation of matter showing individual atoms, molecules, or ions and their interactions to describe chemical processes at the molecular level. |
| repulsive forces | Electrostatic forces between ions of the same charge that push them apart in an ionic solid. |
| Term | Definition |
|---|---|
| delocalized valence electrons | Valence electrons in a metal that are not bound to specific atoms but move freely throughout the entire metallic structure, often described as a 'sea of electrons'. |
| interstitial alloy | An alloy in which smaller atoms occupy the spaces between larger atoms in the crystal lattice, making the structure more rigid and decreasing malleability and ductility. |
| interstitial spaces | The gaps or voids between atoms in a crystal lattice where smaller atoms can fit in an interstitial alloy. |
| lattice | The regular, repeating three-dimensional arrangement of atoms or ions in a crystalline solid. |
| metallic bonding | The type of chemical bonding in metals where valence electrons are delocalized throughout the structure, creating a flexible network of positive ions held together by a mobile electron sea. |
| sea of electrons | A model representing the mobile, delocalized valence electrons that surround positive metal ions in a metallic solid. |
| substitutional alloy | An alloy formed when atoms of comparable size replace or substitute for atoms in the original crystal lattice structure. |
| Term | Definition |
|---|---|
| Lewis diagram | A structural representation of a molecule showing the arrangement of valence electrons as dots and bonds between atoms. |
| molecule | A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound. |
| Term | Definition |
|---|---|
| equivalent structures | Multiple Lewis diagrams of the same molecule that have identical connectivity and differ only in electron placement, contributing equally to the actual structure. |
| formal charge | A calculation used to determine the charge on an individual atom in a molecule, calculated as the number of valence electrons minus the number of non-bonding electrons minus half the number of bonding electrons. |
| Lewis diagram | A structural representation of a molecule showing the arrangement of valence electrons as dots and bonds between atoms. |
| nonequivalent structures | Multiple possible Lewis diagrams of a molecule that differ in connectivity or atom arrangement, with formal charge used to determine which is the best representation. |
| octet rule | A guideline stating that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with eight valence electrons. |
| resonance | The representation of a molecule using two or more equivalent Lewis structures that differ only in the placement of electrons, used to describe bonding when a single structure is inadequate. |
| valence electrons | Electrons in the outermost shell of an atom that participate in bonding and determine many properties of substances. |
| Term | Definition |
|---|---|
| atomic radius | The size of an atom, typically measured as the distance from the nucleus to the outermost electrons. |
| bond angles | The angle formed between two bonds that share a common central atom. |
| bond energy | The average energy required to break a chemical bond between two atoms. |
| bond length | The distance between the nuclei of two bonded atoms, which is affected by bond order and atomic radius. |
| bond order | The number of electron pairs shared between two atoms in a chemical bond, which affects bond energy and bond length. |
| bond polarity | The unequal distribution of electron density in a chemical bond due to differences in electronegativity between atoms. |
| Coulombic repulsion | The electrostatic repulsion between negatively charged electron pairs that determines their spatial arrangement around a central atom. |
| dipole moment | A measure of the separation of positive and negative charge in a polar molecule. |
| electron pair | Two electrons occupying the same orbital, including bonding pairs and lone pairs around a central atom. |
| geometric isomers | Molecules with the same molecular formula but different spatial arrangements of atoms due to restricted rotation around pi bonds. |
| hybrid atomic orbital | An orbital formed by the combination of atomic orbitals on a central atom, used to explain molecular geometry and bonding. |
| hybridization | The mixing of atomic orbitals to form new hybrid orbitals that describe the arrangement of electrons around a central atom. |
| Lewis diagram | A structural representation of a molecule showing the arrangement of valence electrons as dots and bonds between atoms. |
| molecular geometry | The three-dimensional arrangement of atoms around a central atom in a molecule, determined by the positions of bonding and lone pairs. |
| multiple bond | Chemical bonds consisting of more than one electron pair shared between two atoms, such as double or triple bonds. |
| pi bond | A covalent bond formed by sideways overlap of p orbitals, which prevents rotation and is weaker than a sigma bond. |
| polyatomic ion | Charged species composed of two or more atoms bonded together. |
| sigma bond | A covalent bond formed by direct overlap of atomic orbitals along the internuclear axis, allowing rotation around the bond. |
| sp hybridization | The mixing of one s orbital and one p orbital to form two hybrid orbitals with ideal bond angles of 180°. |
| sp2 hybridization | The mixing of one s orbital and two p orbitals to form three hybrid orbitals with ideal bond angles of 120°. |
| sp3 hybridization | The mixing of one s orbital and three p orbitals to form four hybrid orbitals with ideal bond angles of 109.5°. |
| valence orbital | The outermost electron orbitals of an atom that participate in chemical bonding. |
| VSEPR theory | A theory that uses Coulombic repulsion between electron pairs to predict the three-dimensional arrangement of electron pairs and molecular geometry around a central atom. |