periodicchart

GeneralBiologyOnline

Index to All Chapters
Ch. 2 Contents

General
---------Biology
------------------Online------------------wilcox@sunline.net Ch. 2 : The Chemical Context of Life

1.4 Periodic Chart of the Elements

The periodic chart starts with the smallest and lightest atom, hydrogen, and
list each atom in increasing atomic number (# of protons) and atomic weight or mass (protons & neutrons):

The periodic chart reads from left to right, top to bottom, like a page of print.

Locate in the periodic chart those 11 elements listed in Table 2.1 on page 24 of your text. Which elements comprise 96% of a human's body weight?___,___,___,___.

Atom You have been using the term atom, and you have built a few out of protons, neutrons and electrons. Now we need to talk about how small atoms really are; they are so small, no one has ever seen one yet we have still managed to build a working model of how they might appear.

Optional Activity: you might want to play with these online periodic charts; a few clicks should round out your understanding.
http://pearl1.lanl.gov/periodic/default.htm
http://www.chemicalelements.com/

Summary: you should understand

how the periodic chart of the elements is organized
atomic number
atomic mass
which 11 elements are most important in forming fats, carbohydrates and proteins
which 4 elements comprise 96% of a human's body weight
atoms are too small to see, yet we have a working model of their structure

Test your knowledge: Practice Quiz # 43.

Go to Ch. 2 Contents
and click on 1.5 Building a methane molecule.