Page 12 - Alaska A & P Primer

SECTION 2
THE CHEMICAL LEVEL
2.1 Elements and Atoms: The Building Blocks of Matter
2.2 OBJECTIVES
1. Discuss the relationships between matter, mass, elements, compounds, atoms, and subatomic particles
The human body is composed of elements, the most abundant of which are oxygen (O), carbon (C), hydrogen (H) and nitrogen (N). You obtain these elements from the foods you eat and the air you breathe. The smallest unit of an element that re- tains all of the properties of that element is an atom. But, atoms themselves con- tain many subatomic particles, the three most important of which are protons, neu- trons, and electrons. These particles do not vary in quality from one element to an- other; rather, what gives an element its distinctive identification is the quantity of its protons, called its atomic number.
Protons and neutrons contribute nearly all of an atom’s mass; the number of pro- tons and neutrons is an element’s mass number. Heavier and lighter versions of the same element can occur in nature because these versions have different num- bers of neutrons. Different versions of an element are called isotopes. The ten- dency of an atom to be stable or to react readily with other atoms is largely due to the behavior of the electrons within the atom’s outermost electron shell, called its valence shell. Helium, as well as larger atoms with eight electrons in their valence shell, is unlikely to participate in chemical reactions because they are stable. All other atoms tend to accept, donate, or share electrons in a process that brings the electrons in their valence shell to eight (or in the case of hydrogen, to two).
SECTION OBJECTIVES
1. Define the four abundant elements in the body
2. Explain the importance of the inorganic compounds that contribute to life, such as water, salts, acids, and bases
3. Compare and contrast the four important classes of organic (carbon-based) compounds: proteins, carbohydrates, lipids and nucleic acids and functional importance to human life.
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State of Alaska EMS Education Primer - 2016
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