The atomic arrangement of the atoms of an element when it is in its solid state.

The effective size of a nucleus in capturing a thermal neutron (slow neutron). Larger cross sections have a greater probability of neutron capture.

A chemical bond between atoms formed by the sharing of valence electrons.

The movement of heat by a moving liquid or gas. Convection results from the differences in the densities of a material at different temperatures. As a liquid or gas raises in temperature, it

1. Thermal conduction the transfer of heat between two solid materials that are physically touching each other. 2. Electrical conduction the transfer of electrical current through

a substance composed of atoms or ions of two or more elements that are chemically combined. Elements in a compound are present in definite proportions by mass and are bonded with each other

The ratio of change in length per degree centigrade compared to the base length at zero degrees centigrade. The unit of measurement is centimeter per centimeter per degree centigrade (cm/cm/

The emission of absorbed energy as light as the result of a chemical reaction. This occurs in thousands of compounds both organic and inorganic. Chemical glow sticks and fireflies are exampl

The scale for measuring temperature used internationally where the freezing point of water is zero and the boiling point of water at sea level is 100 degrees. To convert from centigrade into

The exposure limit for a substance that should (or in the case of OSHA PEL's "shall") not be exceeded. If instantaneous monitoring is not feasible, then a 15-minute time weighted a

A positively charged ion.

1. Chicago Academy of Science 2. Chemical Abstracts Service (which assigns CAS Numbers to chemicals)

The temperature at which the vapor pressure of a liquid is equal to or slightly greater than the atmospheric pressure of the environment. For water at sea level, its boiling point is 100&deg

a charged particle emitted from the nucleus of some atoms as part of those atoms' radioactive decay. Positively charged beta particles are positrons and negatively charged beta particles are

Compounds that when dissolved in water increase the concentration of hydroxide ions (OH). Bases are proton acceptors. Substances with a pH greater than 7 are considered to basic.

A measurement of area equal to E-24 cm2.

The quantum number that distinguishes orbitals of given n having different shapes. This can be any interger value from 0 to n-1.

This is the number of atoms in a 12g sample of carbon-12 (C12). This is equal to 6.0221367E23 atoms. It is named for Italian chemist Amadeo Avogadro (1776-1856) who first stated the principl

The atomic mass of an element divided by its density.

One-half the distance between two adjacent atoms in crystals of elements. This varies according to interatomic forces.