atom
single particle of an element of the periodic table, such as sodium, oxygen, or carbon
molecule
more than one atom bonded together, such as water (H2O), gaseous oxygen (O2) or salt (NaCl)
compound
molecules that contain at least two types of atoms, such as water (H2O) or salt (NaCl)
positive charge
protons, +
negative charge
electrons, -
nonpolar molecule
molecule with an even distribution of electrons (equal sharing), such as methane (CH4)
ionic bond
bond formed by one atom donating/giving an electron to another atom, such as Na+/Cl-
covalent bond
bond formed by two atoms sharing electrons
polar molecule
molecule with uneven sharing of electrons (such as H2O)
proton
particle in an atom with a positive charge
neutron
particle in an atom with a neutral charge
electron
particle in an atom with negative charge
hydrogen bonds
attractions between partial positive and partial negative charges on polar molecules, such as attractions between water molecules; represented by a dotted line
surface tension
phenomenon that allows insects such as water striders to skate on top of water; caused by strong cohesion between water molecules
cohesion
attraction of water molecules to other water molecules
adhesion
attraction of water molecules to other kinds of molecules such as glass
capillary action
phenomenon where water can move up a thin tube against gravity using adhesion and cohesion, allows water to move up a plant stem
boiling point
temperature at which a substance goes from liquid to gas, such as from liquid water to water vapor
specific heat
the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree)
pH
measure of how acidic/basic a solution is
acidic
0.0-6.9 on the pH scale, higher concentration of hydrogen ions, [H+], such as lemon juice or vinegar
basic
7.1-14.0 on the pH scale, higher concentration of hydroxide ions, [OH-], such as bleach or ammonia
neutral
7.0 on the pH scale, pure water