Basics of Chemistry

Dr. Pamela Gore
Georgia Perimeter College

Objectives

At the completion of this unit, the student can do or answer the following:
  1. What is an atom?
  2. What is an element?
  3. What is a molecule?
  4. What is a compound?
  5. Distinguish between atoms, elements, compounds, and mixtures.
  6. How do neutral atoms become ions?
  7. Locate metals and nonmetals on the Periodic Table of Elements.
  8. What are groups and periods on the Periodical Table of Elements?
  9. How has the arrangement of elements on the periodical table been determined?
  10. How many naturally occurring elements are there?
  11. How many artificial elements are there?
  12. What is the difference between a chemical change and a physical change?
  13. How are ionic and covalent bonds different?
  14. Define and provide examples of these terms: colloid, solution, suspension, heterogeneous, and homogeneous.
  15. What is the difference between a solution and a mixture?
  16. How are these terms used in relation to solutions and mixtures: colloid, suspension, heterogeneous, and homogeneous?

Atomic Structure

The basic building blocks of minerals are the chemical elements.

There are 112 elements known. Of these, 20 have been produced only in the laboratory (artificial elements). The remaining 92 occur naturally.

Atom = The smallest particle of matter with constant properties

An atom contain sub-atomic particles including:
protons (+) positively charged particle
electrons (-) negatively charged particle
neutrons (o) have no charge

Nucleus of atom contains neutrons and protons.

Electrons orbit the nucleus.

In a stable atom (or neutral atom), the number of electrons = the number of protons.

Atomic number - The number of protons in the nucleus determines the atomic number

Change the number of protons and you change the element (also atomic number, atomic mass)

Ion - A charged particle, due to a change in the number of electrons

Cation - positively charged ion (has lost one or more electrons)
Anion - negatively charged ion (has gained one or more electrons)

Isotope - A form of an element with a different number of neutrons

Atomic weight (or mass number) = number of protons + number of neutrons

Mass number   146C 
Atomic number 
                                
                        number of protons = _________
                        number of neutrons = _________



          126C 

                     number of protons = _________
                     number of neutrons = _________
Click here for lecture notes on Atomic Structure

Click here for lecture notes on the Elements

Click here for lecture notes on the Periodic Table

Bonding and Compounds

A compound consists of two or more elements bonded together in definite proportions.
Examples:
Water (H2O)
Halite (table salt) (NaCl)

When an atom combines chemically with another atom, it will either:

  1. Gain electrons (become a negatively charged ion or anion)
  2. Lose electrons (become a positivley charged ion or cation)
  3. Share electrons
  1. Ionic bonding involves electron transfer
    ex. Na+1Cl-1
    An electron has been transferred from the Na to the Cl

  2. Covalent bonding involves electron sharing

  3. Metallic bonding - electrons are free to move
    ex. metals (conduction of electricity)

Click here for lecture notes on compounds and bonds

Chemical Reactions

Click here for lecture notes on reactions

Solutions

Click here for lecture notes on solutions, suspensions, and colloids

Please review the objectives and be sure that you can answer all of the questions based on the readings on this page and on the linked references. Quizzes and exams will be based on the objectives!

Return to Earth & Space Science page

Page created by Dr. Pamela J. W. Gore
May 2000