Biology 1 Chapter 2 Flashcards

acid – molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a
solution
adhesion – attraction between water molecules and other molecules
anion – negative ion that is formed by an atom gaining one or more electrons
atom – the smallest unit of matter that retains all of the chemical properties of an element
atomic mass – calculated mean of the mass number for an element’s isotopes (see also mass number)
atomic mass number – total number of protons and neutrons in an atom

atomic number – total number of protons in an atom
balanced chemical equation – statement of a chemical reaction with the number of each type of atom
equalized for both the products and reactants
base – molecule that donates hydroxide ions or otherwise binds excess hydrogen ions and decreases the
hydrogen ions’ concentration in a solution
buffer – substance that resists a change in pH by absorbing or releasing hydrogen or hydroxide ions
calorie – amount of heat required to change the temperature of one gram of water by one degree
Celsius
capillary action – occurs because water molecules are attracted to charges on the inner surfaces of
narrow tubular structures such as glass tubes, drawing the water molecules to the tubes’ sides
cation – positive ion that is formed by an atom losing one or more electrons
chemical bond – interaction between two or more of the same or different atoms that results in forming
molecules
chemical reaction – process leading to rearranging atoms in molecules
chemical reactivity – the ability to combine and to chemically bond with each other
cohesion – intermolecular forces between water molecules caused by the polar nature of water;
responsible for surface tension
compound – substance composed of molecules consisting of atoms of at least two different elements
covalent bond – type of strong bond formed between two atoms of the same or different elements;
forms when electrons are shared between atoms
dissociation – release of an ion from a molecule such that the original molecule now consists of an ion
and the charged remains of the original, such as when water dissociates into H+ and OH-
electron – negatively charged subatomic particle that resides outside of the nucleus in the electron
orbital; lacks functional mass and has a negative charge of –1 unit
electron configuration – arrangement of electrons in an atom’s electron shell
electron orbital – how electrons are spatially distributed surrounding the nucleus; the area where we
are most likely to find an electron
electron transfer – movement of electrons from one element to another; important in creating ionic
bonds
electronegativity – ability of some elements to attract electrons (often of hydrogen atoms), acquiring
partial negative charges in molecules and creating partial positive charges on the hydrogen atoms
element – one of 118 unique substances that cannot break down into smaller substances; each element
has unique properties and a specified number of protons
enantiomers – molecules that share overall structure and bonding patterns, but differ in how the atoms
are three dimensionally placed such that they are mirror images of each other
equilibrium – steady state of relative reactant and product concentration in reversible chemical
reactions in a closed system
evaporation – change from liquid to gaseous state at a body of water’s surface, plant leaves, or an
organism’s skin

functional group – group of atoms that provides or imparts a specific function to a carbon skeleton
heat of vaporization of water – high amount of energy required for liquid water to turn into water vapor
hydrocarbon – molecule that consists only of carbon and hydrogen
hydrogen bond – weak bond between slightly positively charged hydrogen atoms and slightly negatively
charged atoms in other molecules
hydrophilic – describes ions or polar molecules that interact well with other polar molecules such as
water
hydrophobic – describes uncharged nonpolar molecules that do not interact well with polar molecules
such as water
inert gas – (also, noble gas) element with filled outer electron shell that is unreactive with other atoms
ion – atom or chemical group that does not contain equal numbers of protons and electrons
ionic bond – chemical bond that forms between ions with opposite charges (cations and anions)
irreversible chemical reaction – chemical reaction where reactants proceed unidirectionally to form
products
isotope – one or more forms of an element that have different numbers of neutrons
law of mass action – chemical law stating that the rate of a reaction is proportional to the concentration
of the reacting substances
matter – anything that has mass and occupies space
molecule – two or more atoms chemically bonded together
neutron – uncharged particle that resides in an atom’s nucleus; has a mass of one amu
nonpolar covalent bond – type of covalent bond that forms between atoms when electrons are shared
equally between them
nucleus – core of an atom; contains protons and neutrons
octet rule – rule that atoms are most stable when they hold eight electrons in their outermost shells
orbital – region surrounding the nucleus; contains electron(s)
organic molecule – any molecule containing carbon (except carbon dioxide)
periodic table – organizational chart of elements indicating each element’s atomic number and atomic
mass; provides key information about the elements’ properties
pH scale – scale ranging from zero to 14 that is inversely proportional to the hydrogen ions’
concentration in a solution (0 has more H+ [acidic], 14 has less H+ [basic])
polar covalent bond – type of covalent bond that forms as a result of unequal electron sharing, resulting
in creating slightly positive and negative charged molecule regions
product – molecule that is result of chemical reaction
proton – positively charged particle that resides in the atom’s nucleus; has a mass of one amu and a
charge of +1
radioisotope – isotope that emits radiation comprised of subatomic particles to form more stable
elements
reactant – molecule that takes part in a chemical reaction

reversible chemical reaction – chemical reaction that functions bidirectionally, where products may turn
into reactants if their concentration is great enough
solvent – substance capable of dissolving another substance
specific heat capacity – the amount of heat one gram of a substance must absorb or lose to change its
temperature by one degree Celsius
surface tension – tension at the surface of a body of liquid that prevents the molecules from separating;
created by the attractive cohesive forces between the liquid’s molecules
valence shell – outermost shell of an atom
van der Waals interaction – very weak interaction between molecules due to temporary charges
attracting atoms that are very close together

Adapt