1. Structure and Bonding Flashcards
The number of protons in the nucleus of an element.
Atomic number
Two or more atoms of the same element having the same number of protons in the nucleus but a different number of neutrons
Isotope
The total number of protons and neutrons in the nucleus of a particular atom.
Mass number
The weighted average of the mass of all isotopes of a particular element.
Atomic weight
The number above a particular column in the periodic table. represented by either an Arabic (1 to 8) or Roman (I to VIII) numeral followed by the letter A or B.
Group number
A region of space around the nucleus of an atom that is high in electron density. There are four different kinds called s, p, d, and f.
Orbital
The electrons in the outermost shell of orbitals. determine the properties of a given element
Valence electrons
The joining of two atoms in a stable arrangement. Bonding is a favorable process that leads to lowered energy and increased stability.
Bonding
The structure that results when two or more elements are joined together in a stable arrangement.
Compound
The general rule governing the bonding process for second-row elements. Through bonding, second-row elements attain a complete outer shell of eight valence electrons.
Octet rule
A bond that results from the transfer of electrons from one element to another. Ionic bonds result from strong electrostatic interactions between ions with opposite charges.
Ionic bond
A bond that results from the sharing of electrons between two nuclei. A covalent bond is a two-electron bond.
Covalent bond
A positively charged ion that results from a neutral atom losing one or more electrons.
Cation
A negatively charged ion that results from a neutral atom gaining one or more electrons.
Anion
A compound containing two or more atoms bonded together with covalent bonds.
Molecule
A pair of valence electrons that is not shared with another atom in a covalent bond.
Lone pair of electrons
A representation of a molecule that shows the position of covalent bonds and nonbonding electrons. In Lewis structures, unshared electrons are represented by dots and a two-electron covalent bond is represented by a solid line.
Lewis structure
The electronic charge assigned to individual atoms in a Lewis structure. The formal charge is calculated by subtracting an atom’s unshared electrons and half of its shared electrons from the number of valence electrons that a neutral atom would possess.
Formal charge
Two different compounds that have the same molecular formula.
Isomers
Two compounds that have the same molecular formula, but differ in the way the atoms are connected to each other.
Constitutional isomers
Two or more structures of a molecule that differ in the placement of π bonds and nonbonded electrons. The placement of atoms and σ bonds stays the same.
Resonance structures
An atom other than carbon or hydrogen. Common heteroatoms in organic chemistry are nitrogen, oxygen, sulfur, phosphorus, and the halogens.
Heteroatom
A structure that is a weighted composite of all possible resonance structures. The resonance hybrid shows the delocalization of electron density due to the different locations of electrons in individual resonance structures.
Resonance hybrid
Valence shell electron pair repulsion theory. A theory that determines the three-dimensional shape of a molecule by the number of groups surrounding a central atom. The most stable arrangement keeps the groups as far away from each other as possible.
VSEPR theory
