Chemical Elements and Atomic Structure

Objectives

• list the major chemical elements involved in human structure and function;
• describe the structure of atoms;
• distinguish atomic mass from atomic weight; and
• define ion, electrolyte, and free radical.
   

Why is there no difference in the chemical behavior of different isotopes of the same element?

 1. What is an element? Which six elements are most abundant in the human body? What is a trace element?

 2. What is an electron shell?

 3. Define atomic number, atomic mass, and atomic weight.

 4. How do isotopes of the same element differ from each other?

 5. How is an ion different from an atom?

Molecules, Compounds, and Chemical Bonds

Objectives

When you have completed this section, you should be able to

• describe the different types of chemical bonds and explain how they form;
• show how compounds are represented by chemical formulae;
• define isomer and discuss the significance of isomers; and
• calculate the molecular weight of compounds.

Would it be logical to assume that ionic bonds are common in the human body? Why or why not?

Key Point Review

 6. How do isomers differ from each other? What is the difference between an isomer and an isotope?

 7. What does chemical bonding have to do with full electron shells?

 8. How is an ionic bond formed?

 9. What is a covalent bond? How do single and double covalent bonds differ? How do nonpolar and polar covalent bonds differ?

10. What is a hydrogen bond? Why do hydrogen bonds depend on the existence of polar covalent bonds?

Mixtures

Objectives

When you have completed this section, you should be able to

• define mixture and distinguish between mixtures and compounds;
• show how three kinds of mixtures differ from each other; and
• describe some of the ways in which the concentration of a mixture can be expressed, and explain why different expressions are used for different purposes.
  

Air is a mixture of nitrogen, oxygen, carbon dioxide, and other gases. Would you classify it as a solution, colloid, or suspension? Explain.

Key Point Review

 11. Distinguish between a mixture, solution, colloid, and suspension. Give examples of the last three.

 12. Explain why it may be inappropriate for some purposes to express chemical concentrations as percentages.

 13. What is a mole? How many particles are in 1 mole?

 14. Explain how molarity is calculated.

 15. Explain what is meant by milliequivalents per liter. What substances are measured in this way?

Acids, Bases, and pH

Objectives

When you have completed this section, you should be able to

• define acid, base, and pH;
• describe the pH scale; and
• discuss the role of buffers in the body's acid-base balance.

Think About It

A pH of 7.20 is slightly alkaline, yet a blood pH of 7.20 is called acidosis. Why do you think it is called this?

Key Point Review

 16. Define acid and base, and explain how acids and bases affect the pH of a solution.

 17. Explain why each digit of the pH scale represents a 10-fold difference in hydrogen ion concentration.

 18. What is a buffer? Why are buffers important?

Chemical Reactions

Objectives

When you have completed this section, you should be able to

• define chemical reaction;
• recognize the reactants and products in a chemical equation and determine whether the equation is balanced;
• list and define the fundamental types of chemical reactions; and
• describe the factors that govern the speed and direction of a reaction.

Key Point Review

19. What are the substances that enter into a chemical reaction called? What is the term for new substances that result from the reaction?

20. What are the differences between decomposition, synthesis, and exchange reactions? Write a generalized equation for each type using the letters A through D.

21. List three factors that affect the rates of chemical reactions. Explain how each factor works.

Energy

Objectives

When you have completed this section, you should be able to

• define work and energy;
• list some biologically important forms of energy; and
• discuss ionizing radiation and its biological effects.

Key Point Review

22. Define energy and distinguish kinetic from potential energy.

23. Discuss the three forms of ionizing radiation, noting the distinctions between them.

24. What is the greatest source of background radiation for the average U.S. resident? How can it be avoided?

25. How much radiation does the average U.S. resident absorb in a year? What is considered the safe limit of occupational exposure for a radiation therapist?

Thermodynamics and Metabolism

Objectives

When you have completed this section, you should be able to

• state the first two laws of thermodynamics and explain why these laws are relevant to biological function;
• describe the nature of endergonic and exergonic reactions;
• describe the nature of oxidation and reduction reactions; and
• define metabolism and explain how catabolism and anabolism differ.

Key Point Review

26. Define metabolism, catabolism, and anabolism.

27. What does oxidation mean? What does reduction mean? Which of them is endergonic and which is exergonic?

28. When sodium chloride is formed, which element-sodium or chlorine-is oxidized? Which one is reduced?

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