physical science crossword unit 11 & 13

valence electrons

The electrons that are involved in bond formation, usually those in an atom's outer shell.

Solubility

The amount of solute that will dissolve in a specified volume or mass of solvent (at a given temperature) to produce a saturated solution.

alkali metals

The elements in Group 1A of the periodic table, except for hydrogen

compound

A pure substance composed of two or more elements chemically bonded in a definite, fixed ratio by mass.

mixture

A type of matter composed of varying proportions of two or more substances that are just physically mixed, not chemically bonded.

groups

The vertical columns in the periodic table.

noble gases

The elements of Group 8A of the periodic table

alkaline earth metals

The elements in Group 2A of the periodic table

valence shell

An atom's outer shell, which contains the valence electrons.

periods

The horizontal rows in the periodic table, organizing the elements on the basis of atomic numbers.

inner transition elements

The lanthanides and actinides, the two rows at the bottom of the periodic table, make up the inner transition elements.

solution

A mixture that is uniform throughout, also called a homogeneous mixture.

halogens

The elements in Group 7A of the periodic table

representative elements

Those in Groups 1A through 8A in the periodic table.

ionization energy

The amount of energy it takes to remove an electron from an atom.

ion

An atom, or chemical combination of atoms, that has a net electric charge because of a gain or loss of electrons.

molecule

An electrically neutral particle composed of two or more atoms chemically bonded.

nonmetal

An element whose atoms tend to gain (or share) electrons during chemical reactions.

metal

An element whose atoms tend to lose valence electrons during chemical reactions.

chemistry

The study of the composition and structure of matter (anything that has mass) and the chemical reactions by which substances are changed into other substances.

element

A pure substance in which all the atoms have the same number of protons; that is, they have the same atomic number.

periodic law

The properties of elements are periodic functions of their atomic numbers.

electron configuration

The order of electrons in the energy levels of their atoms.

transition elements

The B group of elements in the periodic table.

allotropes

Two or more forms of the same element that have different bonding structures in the same physical phase.

decomposition reaction

AB --> A + B

exothermic reactions

A reaction that has a net release of energy to the surroundings.

products

The substances formed during a chemical reaction.

combustion reaction

A reaction in which a substance reacts with oxygen to burst into flame and form an oxide.

reactants

The original substances in a chemical reaction.

single-replacement reaction

Reactions in which one element replaces another that is in a compound

activation energy

The energy necessary to start a chemical reaction

pH

A measure (on a logarithmic scale) of the hydrogen ion (or hydronium ion) concentration in a solution.

Comination reaction

A + B --> AB

equilbrium

In chemistry, a dynamic process in which the reactants are combining to form the products at the same rate at which the products are combining to form the reactants.

salt

An ionic compound composed of any cation except H+ and any anion except OH-

Avogardo's number

the number of entities in a mole.

molarity

A measure of solution concentration in terms of moles of solute per liter of solution.

single-replacement reaction

A + BC --> B + AC

mole

The quantity of a substance that contains as many elementary units as there are atoms in exactly 12g of carbon

Acid

A substance that gives hydrogen ions, H+ (or hydronium ions, H3O+) in water (Arrhenius definition).

activity series

A list of elements in order of relative tendency to lose electrons to ions of another metal or to hydrogen ions.

chemical reaction

A change that alters the chemical composition of a substance and hence forms one or more new substances.

acid-base reaction

The H+ of an acid unites with the OH- of a base to form water, while the cation of the base combines with the anion of the acid to form a salt

double-replacement reaction

AB + CD --> AD + CB

acid-carbonate reaction

An acid and a carbonate (or hydrogen carbonate) react to give carbon dioxide, water, and a salt.

catalyst

A substance that increases the rate of reaction but is not itself consumed in the reaction.

acid-base reaction

also called a neutralization reaction

decomposition reaction

One in which only one reactant is present and decomposes into two (or more) products:

reduction

Occurs when oxygen combines with a substance or when an atom or ion gains electrons.

combination reaction

A reaction in which at least two reactants combine to form just one product

double replacement reaction

Reactions in which the positive and negative components of the two compounds "change partners."

endothermic reaction

A reaction that causes a net absorption of energy from the surroundings to occur.

oxidation

Occurs when oxygen combines with a substance or when an atom or ion loses electrons.

base

A substance that gives hydrogen ions, OH-, in water (Arrhenius definition).

activation energy

The energy necessary to start a chemical reaction; a measure of the minimum kinetic energy that colliding molecules must possess in order to react chemically.

precipitate

An insoluble solid that appears when two liquids (usually aqueous solutions) are mixed.