Chemical Context of Life - Vocabulary Flashcards

A complete list of chemistry vocabulary terms and their definitions based on the lecture crossword clues.

ELECTRONEGATIVITY

The attraction of a given atom for the electrons of a covalent bond.

PROTON

A subatomic particle with a single positive electrical charge, with a mass of about $1.7 \times 10^{-24}\,g$, found in the nucleus of an atom.

IONIC BOND

A chemical bond resulting from the attraction between oppositely charged ions.

HYDROGEN BOND

A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.

ELECTRON

A subatomic particle with a single negative electrical charge and a mass about $\frac{1}{2,000}$ that of a neutron or proton. One or more electrons move around the nucleus of an atom.

CHEMICAL REACTION

The making and breaking of chemical bonds, leading to changes in the composition of matter.

CHEMICAL BOND

An attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.

CHEMICAL EQUILIBRIUM

In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.

ATOMIC NUCLEUS

Where protons and neutrons are located, at the center of an atom

VALENCE ELECTRON

An electron in the outermost electron shell.

ESSENTIAL ELEMENT

A chemical element required for an organism to survive, grow, and reproduce.

POLAR COVALENT BOND

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

CATION

A positively charged ion.

ION

An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.

NONPOLAR COVALENT BOND

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.

VALENCE

The bonding capacity of a given atom; the number of covalent bonds that an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell.

DOUBLE BOND

A double covalent bond; the sharing of two pairs of valence electrons by two atoms.

SINGLE BOND

A single covalent bond; the sharing of a pair of valence electrons by two atoms.

NEUTRON

A subatomic particle having no electrical charge (electrically neutral), with a mass of about $1.7 \times 10^{-24}\,g$, found in the nucleus of an atom.

ISOTOPE

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.

ATOMIC MASS

The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. (For an element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighted by their abundance.) atomic nucleus An atom's dense central core, containing protons and neutrons.

HALF LIFE

The amount of time it takes for $50\%$ of a sample of a radioactive isotope to decay.

COVALENT BOND

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.

ELEMENT

Any substance that cannot be broken down to any other substance by chemical reactions.

DALTON

A measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu.

PRODUCT

A material resulting from a chemical reaction.

VAN DER WAALS INTERACTIONS

Weak attractions between molecules or parts of molecules that result from transient local partial charges.

ELECTRON SHELL

An energy level of electrons at a characteristic average distance from the nucleus of an atom.

MOLECULE

Two or more atoms held together by covalent bonds.

POTENTIAL ENERGY

The energy that matter possesses as a result of its location or spatial arrangement (structure).

ENERGY

The capacity to cause change, especially to do work (to move matter against an opposing force).

RADIOMETRIC DATING

A method for determining the absolute age of rocks and fossils, based on the half -life of radioactive isotopes.

TRACE ELEMENT

An element indispensable for life but required in extremely minute amounts.

RADIOACTIVE ISOTOPE

An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy.

MASS NUMBER

The total number of protons and neutrons in an atom's nucleus.

EMERGENT PROPERTIES

New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases.

ionic compound (or salt)

A compound resulting from the formation of an ionic bond; also called a salt.

ATOMIC NUMBER

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript.

SALT

A compound resulting from the formation of an ionic bond; also called an ionic compound.

REACTANT

A starting material in a chemical reaction.

VALENCE SHELL

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

ORBITAL

The three-dimensional space where an electron is found $90\%$ of the time.

COMPOUND

A substance consisting of two or more different elements combined in a fixed ratio.

ATOM

The smallest unit of matter that retains the properties of an element.