Chapter 1-Atoms, Elements, and Radioactivity
                         Physical Geology Illustrated Vocabulary
Cochise College                                    
Geology Home Page  
Atoms. Elements, and Radioactivity
Roger Weller, geology instructor  
copyright 2018-Roger Weller
last edited: 3/19/18

Chapter 1

Periodic Table of the Elements

alpha particle

-is a form of radioactivity, consisting of a Helium-4 nucleus being emitted from the nucleus
of a radioactive isotope.
-alpha decay-Opal's Pals



-is the smallest part of an element that retains the characteristics of that element. 
It consists of a small, dense nucleus made up of protons and neutrons surrounded by electrons
orbiting the nucleus at a distance.


atomic mass number

-For a particular isotope it is the number of protons plus neutrons within the atomic nucleus.
-atomic mass  number-Opal's Pals

atomic nucleus

-is a small, dense structure in the center of an atom containing protons and neutrons. 
(see atom.)


atomic number

-is determined by the number of protons within an atomic nucleus.
-atomic number-Opal's Pals


atomic weight

-is a value representing the weight of one atom of an element compared to the weight of one
atom of oxygen 16.


beta particle or beta ray

-is a form of radioactivity consisting of the emission of a high speed electron from an atomic


chemical compound

-consists of chemical elements combined together in a fixed ratio.


chemical property

-is the identification of a mineral through the use of chemicals. 
For example, hydrochloric acid applied to the mineral
calcite produces bubbles of carbon dioxide.


covalent bond

-is a type of bonding in chemicals where electron pairs are shared between adjacent atoms.


-is a measurement of the mass of an object compared to its volume; often expressed in terms of
grams per cubic centimeter.
-density-Opal's Pals


electric force

-is responsible for the attraction between electrons and protons



-is a negatively charged subatomic particle that is usually found in an orbit about an atomic
-electron-Opal's Pals



-is a pure material in which all of the atoms have the same number of protons in each atomic
nucleus.  Only 92 different varieties occur naturally on the Earth.

-is a push or a pull.  There are only 4 forces that hold the Universe together

      strong nuclear force-binds neutrons and protons together
      weak nuclear force-holds a neutron together
      electromagnetic force-holds atoms together
      gravity-holds planets, stars, and galaxies together


gamma ray

-is a high energy x ray.



-is an atom or group of atoms with excess electrical charge, not electrically neutral.
-ion-Opal's Pals


ionic bond

-is a chemical bond that holds a material together by the electrostatic attraction of the ions that
compose the material.



-is a variety of a chemical element, identified by the number of protons plus neutrons in the atomic
-isotopes-Opal's Pals


-is an electrically neutral sub-atomic particle of the approximately the same mass as a proton
and found in the atomic nucleus. Its primary function is to bind the electrically repulsive protons
together in the atomic nucleus.


nuclear fission

-is the process where a large atomic nucleus breaks into smaller atomic nuclei.


nuclear fusion

-occurs when two small atomic nuclei are fused together to produce a larger atomic nucleus. 
As long as the atomic nuclei are small the fusion process releases large quantities of energy.
-nuclear fusion-Opal's Pals



-is a positive charged, heavy subatomic particle found in the atomic nucleus.
-proton-Opal's Pals


radiation effects

-are the damaging effects of radioactivity on biological matter which includes mutations, cell
rupture, cancer, and death.


radioactive half life

-is the amount of time it takes for half of the atoms of a specific radioactive isotope to decay.



-is the spontaneous decay of an atomic nucleus.



-is the element number 14; semi-metallic.  It does not occur naturally in its pure form on the surface
of the Earth.




-is a  lemon yellow, transparent to translucent element that burns in an oxygen atmosphere.

-sulfur crystals from Michigan 

-sulfur, conchoidal fracture 
-sulfur, drusy 


ultraviolet light

-is where light just outside of the normal visible spectrum, just past violet. 
This light with a shorter wavelength than violet light is responsible for sunburn on bright, sunny