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64 terms

Campbell Biology Chapter 2

Chapter 2 Campbell Biology vocabulary and questions
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Matter
anything that occupies space and has mass
Element
a substance that cannot be broken down
Compound
a substance consisting of two or more different elements combined in a fixed ratio
Trace Elements
essential in human body, but only in minute quantities
Atom
smallest unit of matter
Proton
(+) charged subatomic particle
Electron
(-) charged subatomic particle
Neutron
(n) charged subatomic particle
Nucleus
atom's core
Atomic Number
number assigned to an element by the number of protons it contains
Mass Number
sum of the number of protons and neutrons in an element
Atomic Mass
atom's weight
Isotopes
a form of an element with different # of protons
Radioactive Isotopes
an unstable form of an element with different # of protons
Electron Shells
number of electrons for an element to be stable
Chemical Bonds
atoms linked and held by attractions
Covalent Bond
atoms linked and sharing valence electrons
Molecule
linked atoms
Elecronegativity
attractions for shared electrons
Nonpolar Covalent Bonds
elements with equally shared electrons
Polar Covalent Bonds
slightly electromagnetic bonds
Polar Molecule
a molecule with slight unequal distribution of charges
Ionic Bond
ions with opposite charges are held together
Salt
ionic compound w/ metal and nonmetal
Hydrogen Bond
a bond w/ a H+ ion
Chemical Reaction
the breaking and making of chemical bonds leading to changes in the composition of matter
Reactants
starting materials in a chemical reaction
Product
ending materials in a chemical reaction
Cohesion
tendency for same molecules to stick together
Adhesion
clinging of one substance to another
Surface Tension
a measure of how difficult it is to stretch or break the surface of a liquid
Heat
the amount of energy associated with the movement of atoms
Temperature
the intensity of heat
Evaporative Cooling
when a substance evaporates and leaves a surface cooler
Solution
a liquid consisting of a uniform mixture of two or more substances
Solvent
the dissolving agent in a solution
Solute
the substance dissolved in a solution
Aqueous Solution
a solution in which water is the solvent
Acid
substance that adds H+ ions in solution
Base
substance that removes H+ions in solution
pH Scale
scale to describe how acidic or basic a solution is
Buffers
substance that minimize changes in pH
Acid Precipitation
precipitation w/ pH lower than 5.2
Ocean Acidification
CO2 dissolving in sea water and raising the acidity
_______ are the smallest part of an element that retains all properties of that element
atom
_______ cannot be broken down
elements
_______ is not contained in nucleus
electrons
an element with different # of protons
isotope
unstable variation of an element with different # of protons
radioactive isotope
Electron shells have _______, _______, and _______ electrons
2, 8, 18
_______ bonding involves the transfer of electrons
ionic
_______ bonding involves the sharing of electrons
covalent
elements have differing electronegativity are _______
polar
elements have the same electronegativity are _______
nonpolar
_______ leads to surface tension in water
hydrogen bonding
sweating is an example of _______
evaporative cooling
hydrogen ions = (_______)
H+
hydroxide ions = (_______)
OH-
substances that remove H+ ions are _______
bases
substances that add H+ are _______
acids
difference between pH of 6 and 7 is _______
10X
when a _______ takes place, compounds change their properties
chemical reaction
matter neither gained nor destroyed, called _______
Law of Conservation of Mass
_______ elements essential to life
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