AP Biology Unit 1, AP Biology Unit 2
Matter - answer✔✔Anything that takes up space and has mass.
Element - answer✔✔Substance that cannot be broken down to other substances through
chemical reactions. Each has a symbol. 92 occurring in nature.
Compound - answer✔✔Substance consisting of two or more different elements combined in a
fixed ratio.
*Characteristics different than those of its elements
CHON - answer✔✔4 elements essential to life
Trace Elements - answer✔✔Required by an organism only in minute quantities.
Atom - answer✔✔Smallest unit of matter that retains the properties of an element. Composed of
subatomic particles. Mostly empty space.
Subatomic particles - answer✔✔Neutrons, protons, electrons. Make up atoms.
Proton - answer✔✔One unit of positive charge. Approximately one dalton. Located in nucleus.
Electron - answer✔✔One unit of negative charge. Located outside of nucleus.
Atomic Nucleus - answer✔✔Dense core packed with protons and neutrons.
Neutrons - answer✔✔Electrically neutral. Approximately one dalton.
Atomic Number - answer✔✔The number of protons (which is unique to that element) and
written as a subscript to left of element symbol. Also tells us number of electrons since P=E if
atom is neutral
Mass Number - answer✔✔Sum of the protons and the neutrons. An approximation of the atomic
mass.
Isotopes - answer✔✔Same number of protons, but different number of neutrons and therefore
different mass. Same element.
Radioactive Isotope - answer✔✔One in which the nucleus decays spontaneously, giving off
particles and energy. Can decay to a different element. Have useful applications.
, ©THEBRIGHT EXAM STUDY SOLUTIONS 8/21/2024 1:28 PM
Energy - answer✔✔Capacity to cause change
Potential Energy - answer✔✔Energy matter possesses because of its location or structure.
Electrons have this based on distance from nucleus.
Electron Shells - answer✔✔Where electrons are found, each with characteristic average distance
and energy level. Electrons can change these by absorbing or losing energy.
Valence Electrons - answer✔✔Electrons in the outermost shell.
Chemical Bonds - answer✔✔The attraction that holds atoms together during an interaction.
Covalent Bond - answer✔✔Sharing of a pair of valence electrons by two atoms.
Molecule - answer✔✔Two or more atoms held together by covalent bonds.
Single Bond - answer✔✔One pair of shared electrons.
Structural Formula - answer✔✔H--H. Notation which represents both atoms and bonding.
Double Bond - answer✔✔Sharing two pairs of valence electrons.
Valence - answer✔✔Bonding capacity. Equal to the number of unpaired electrons required to
complete the outermost (valence) shell.
Electronegativity - answer✔✔The attraction of a particular kind of atom for the electrons of a
covalent bond.
Nonpolar Covalent Bond - answer✔✔Covalent bond in which electrons are shared equally.
Polar Covalent Bond - answer✔✔Where one atom is bonded to a more electronegative atom and
the electrons of the bond are not shared equally.
Ionic Bonds - answer✔✔The attraction of cations and anions. The transfer of electrons creates
ions which form an ionic bond.
Ion - answer✔✔A charged atom.
Cation - answer✔✔A positively charged atom.
Anion - answer✔✔A negatively charged atom.
Ionic Compounds - answer✔✔Or Salts. Compounds formed by ionic bonds.
Hydrogen Bond - answer✔✔When a hydrogen atom covalently bonded to an electronegative
atom is also attracted to another electronegative atom.