Chapter 2: The Chemical Context of Life Flashcards
Valence shell
The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.
Cation
A positively charged ion.
Trace elements
An element indispensable for life but required in extremely minute amounts.
Ionic compounds
A compound resulting from the formation of an ionic bond; also called a salt.
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.)
Van der Waals interactions
Weak attractions between molecules or parts of molecules that result from transient local partial charges.
Protons
A subatomic particle with a single positive electrical charge, with a mass of about 1.7 times 10 to the negative 24 g, found in the nucleus of an atom.
Radioactive isotope
An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy.
Reactants
A starting material in a chemical reaction.
Anion
A negatively charged ion.
Element
Any substance that cannot be broken down to any other substance by chemical reactions.
Valence electrons
An electron in the outermost electron shell.
Salts
A compound resulting from the formation of an ionic bond; also called an ionic compound.
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).
Molecule
Two or more atoms held together by covalent bonds.
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.
Ionic bond
A chemical bond resulting from the attraction between oppositely charged ions.