CHEMISTRY MIDTERM STUDY SHEET

Atomic radius

________ decreases as you go from left to right across a period and increases as you go down a group due to electron shielding.

Kinetic energy increases

________ when temperature increases and decreases when temperature decreases.

Dipole Dipole attraction

________ occurs between polar molecules and is stronger than London dispersion forces.

Potential energy increases

________ during melting and boiling and decreases during condensation and freezing.

protons

positively charged

neutrons

no charge

electrons

negatively charged

atomic number

the amount of protons in an atom

atomic mass

the average atomic mass of all of the naturally occurring isotopes

isotope

same number of protons but different number of neutrons

valence electrons

electrons found on the outermost shell of an atom

Contributions made by J.J. Thompson

discovered the electron using the cathode ray tube

Ernest Rutherford

discovered the proton, positive nucleus, and that most of the atom is empty space through the gold foil experiment

Half-life

the amount of time it takes for half of a radioactive element to decay or become stable

Fission

the splitting of an atom

Fusion

the joining of two nuclei into one new nucleus

The Big Bang Theory

a theory that suggests that the universe was created as a result of an extremely large explosion

atomic radius

the size of the atom

electronegativity

the ability for an atom to attract electrons

ionization energy

the amount of energy needed to take the most loosely bound electron

Ionic compounds

form between metals and nonmetals, metals and polyatomic ions, polyatomic ions and nonmetals, and two polyatomic ions

ionic bonding

electrons are transferred from one element to another

Covalent compounds

are between two or more nonmetals

covalent bonding

means that electrons are shared between nonmetals

melting

(solid to liquid)

boiling

(liquid to gas)

condensation

(gas to liquid)

freezing

(liquid to solid)

sublimation

(solid to gas skipping the liquid step)

deposition

(gas to solid skipping the liquid step)

Intermolecular forces

a force that occurs between molecules