Studied by 12 people
C, H, O , N
most common elements in living things
ATOM
smallest unit of an element that retains the element's
ATOMIC NUMBER
fixed number of protons in the atomic nucleus
ATOMIC MASS UNIT (AMU)
mass of a subatomic particle
ATOMIC MASS
the total number of protons neutrons
ISOTOPES
atoms of the same element with varying numbers of neutrons
RADIOISOTOPE
unstable and tend to decay to a more stable isotope
ORBITALS
regions of 3-D space in which electrons move
VALENCE SHELL
outermost electron shell, which the most energetic electrons occupy
INORGANIC COMPOUNDS
small, simple substances (ex: water, simple acids & bases, and simple salts)
ORGANIC COMPOUNDS
large, complex carbon-containing compounds
MOLECULAR MASS OF A COMPOUND
the sum of the atomic masses of the component atoms of a single molecule
1 MOLE
the amount of a compound whose mass in grams is equivalent to its molecular mass
BOND ENERGY
energy necessary to break a chemical bond
COVALENT BONDS
share electrons between atoms to fill each atom's valence shell
COVALENT MOLECULE
consists of atoms joined by covalent bonds
Ex. hydrogen gas (H2)
COVALENT COMPOUND
unlike atoms linked by covalent bonds (ex methane gas CH4)
LEWIS STRUCTURE
a simple way of representing valence electrons by placing dots around the element's chemical symbol
ORBITAL HYBRIDIZATION
atoms form covalent bonds that require orbitals in valence shells to become rearranged, affecting the shape of the end molecule
ELECTRONEGATIVITY
measure of an atom's attraction for shared electrons in chemical bonds
NONPOLAR COVALENT BOND
covalently bonded atoms with similar electronegativities/ similar shared electrons
POLAR COVALENT BOND
covalent bond between atoms that differ in electronegativity
ION
an atom or group
HYDROGEN BONDS
relatively weak bonds that are very important in living organisms
VAN DER WAALS
Weak attractions between molecules or parts of molecules that result from transient local partial charges.
COHESION
occurs when water molecules stick to one another
ADHESION
the ability of water to stick to other substances
CAPILLARY ACTION
tendency of water to move in narrow tubes
SURFACE TENSION
occurs when molecules at water's surface crowd together, producing a strong layer
HYDRATION
the process in which an ion is surrounded by water molecules arranged in a specific manner
ACID
substance that dissociates in solution to yield hydrogen ions & anion; a proton donor
BASE
substance that dissociates in solution to yield a hydroxide ion and cation; a proton acceptor
BUFFER
a substance that resists changes in pH when acid or base is added
SALT
compound in which the hydrogen ion of an acid is replaced by some other cation
Note 
Flashcard (21)