Radioactivity, Chemistry

Half life

Length of time required for half of the radioactive atoms in a sample to decay

Isotope

Atoms with the same number of protons but different numbers of neutrons

Atomic number

The number of protons in the nucleus of an atom

Mass number

the total number of protons and neutrons in the nucleus of an atom

Fission

Process in which heavy atomic nuclei split into smaller, lighter nuclei

Fusion

Lighter nuclei combine to form heavier nucleus with release of energy

Alpha particle

particle emitted by a radioactive source that contains two protons and two neutrons, and has a double positive charge

Beta particle

a high-speed electron or positron emitted in the decay of a radioactive isotope

Gamma wave

High energy Electromagnetic radiation

Radioactivity

The emission of elementary particles by some atoms when their unstable nuclei disintegrate.

Strong force

Holds particles together in the atomic nucleus. This is the strongest force known in nature.

atom

the smallest object that retains properties of an element. Composed of electrons and a nucleus (containing protons and neutrons)

atomic number

number of protons in an element

chemical equation

an expression of a fundamental change in the chemical substance

compound

two or more atoms joined together chemically, with covalent or ionic bonds

covalent bonds

when two atoms share at least one pair of electrons

Radioactive decay

change of an element into a different element, usually with some other particle(s) of energy emitted

density

mass per unit volume of a substance

endothermic

process that absorbs heat from its surroundings as the reaction proceeds

half life

the amount of time it takes for half an initial amount to disintegrate

ion

removing or adding electrons to an atom creates an ... (a charged object very similar to an attom)

ionic bond

when two oppositely charged atoms share at least one pair of electrons but the electrons spend more time near one of the atoms than the other

Le Chatlier's Principle

states that a system at equilibrium will oppose any change in the equilibrium conditions

mass number

the number of protons and neutrons in an atom

molar

a term expressing molarity, the number of moles of solute per liters of solution

moles

a collection of 6.022 * 10 to the 23 power number of objects. Usually used to mean molecules

molecular mass

the combined mass (as given on the periodic table) of all the elements in a compound

percent composition

expresses the mass ratio between different elements in a compound

valence electrons

The electrons in the outermost shell of an atom

volume

Measures the size of an object using length measurements in three dimensions

wave

A signal which propagates through space

wavelength

On a periodic curve, the length between two consecutive troughs (low points) or peaks (high points)