Matter
Anything that has mass and takes up space
element
A substance that cannot be broken down into simpler substances
compound
A substance made up of atoms of two or more different elements in a fixed ratio joined by chemical bonds
atom
the smallest unit of matter that retains the properties of an element
subatomic particles
Tiny bits of matter that are the building blocks of an atom
Neutron
A subatomic particle that has no charge and that is found in the nucleus of an atom
Protons
A subatomic particle that has a positive charge and that is found in the nucleus of an atom
Electron
A subatomic particle that has a negative charge
atomic nucleus
An atom's dense central core, containing protons and neutrons.
atomic number
the number of protons in the nucleus of an atom
mass number
the sum of the number of neutrons and protons in an atomic nucleus
atomic mass
The total mass of an atom, which is the mass in grams of 1 mole of the atom.
isotopes
Atoms with the same number of protons but different numbers of neutrons
Energy
the capacity to cause change
potential energy
energy that matter possesses because of its location or structure
electron shells
An energy level representing the distance of an electron from the nucleus of an atom.
valance electrons
the number of electrons in the outermost energy level
valance shell
the outermost shell of an atom containing the valence electrons.
chemical bond
An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms.
covalent bond
a type of strong bond between two atoms share one or more pairs of valance electrons
Molecule
two or more atoms held together by covalent bonds
single bond
a covalent bond in which two atoms share one pair of valance electrons are shared between two atoms
double bond
A covalent bond in which two pairs of valance electrons are shared between two atoms
Valance
bonding capacity of a given atom; the number of covalent bonds an atom can form, usually equals the number of unpaired electrons in its outermost valance shell
nonpolar covalent bond
A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.
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.
Electronegativity
The attraction of a given atom for the electrons of a covalent bond.
ionic bond
A chemical bond resulting from the attraction between oppositely charged ions.
Ions
An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.
Cation
A positively charged ion
Anion
A negatively charged ion
hydrogen bond
A type of weak chemical bond 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.
vaan der waals interactions
attractions between molecules that are close together as a result of these charges
chemical reaction
the making and breaking of chemical bonds, leading to changes in the composition of matter
polar molecule
molecule (such as water) with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end
Cohesion
the linking together of like molecules, often by hydrogen bonds
Adhesion
the clinging of one substance to another, such as water to plant cell walls by means of hydrogen bonds
surface tension
A measure of how difficult it is to stretch or break the surface of a liquid
kinetic energy
energy of motion
thermal energy
Kinetic energy due to the random motion of atoms and molecules; energy in its most random form.
Temperature
the average kinetic energy of particles in a substance
heat
thermal energy in transfer from one body of matter to another
specific heat
The amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1°C.
heat of vaporization
the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state
Solution
A homogeneous mixture of two or more substances
Solvent
A liquid substance capable of dissolving other substances
Solute
A substance that is dissolved in a solution.
aqueous solution
one in which the solute is dissolved in water; water is the solvent
hydration shell
the sphere of water molecules around each dissolved ion
Hydrophobic
Water fearing
Hydrophilic
water loving
hydrogen ion
a single proton with a charge of 1+ (H+)
hydroxide ion
a water molecule that has lost a proton (OH-)
hydronium ion
the proton binds to the other water molecule(H3O+)
Acid
A substance that increases the hydrogen ion concentration of a solution.
Base
A substance that decreases the hydrogen ion concentration in a solution.
pH scale
measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14
pH
a measure of the hydrogen ion concentration of a solution
pH range: Which is the most acidic?
0
pH range: which is the most basic?
14
Buffers
solution that contains a weak acid and its corresponding base
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