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Chemistry101 - Chemistry Concepts 1 As indicated in our...

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Chemistry Concepts - 1 As indicated in our course introduction, much of Biology 101 emphasizes the study of cells, which structurally and functionally are an aggregate of atoms and molecules (chemicals) working together, and which require the energy of these chemicals to stay alive and to function. Atoms and molecules combine in various ways (to be discussed) to form the structures of the cells and tissues of which living organisms are composed, and provide the energy to sustain these cells and tissues. In our first unit of lectures we will discuss the basic structure of atoms and molecules to help us understand the biological concepts that will follow in this course. Atoms The atom is the fundamental unit of matter. And matter is any substance of the universe (gas, liquid, solid, plasma). More simply, matter is stuff or anything that has mass and occupies space. Living organisms are composed of matter. Matter can be changed from one form to another in a chemical reaction, a process in which different forms of matter combine or break apart. There are 92 naturally occurring atoms on earth. We have about 108 total different kinds of atoms, because humans have been able to make atoms through nuclear reactions. Each type of atom is composed of hundreds of smaller, subatomic particles, three of which we shall discuss. The proportion of these subatomic particles in any given atom identifies the kind of atom. An element is a substance composed exclusively of one kind of atom. An element is a pure chemical that cannot be separated into or converted into a simpler substance. An atom is the smallest portion of an element that retains the properties of the element. Each element (atom) has a name and a one- or two-letter abbreviation. The Periodic Table of Elements shows these, along with other useful information about each element. (See Appendix D of your Biology 101 Handbook.) Although we have 92 different elements (formed from the 92 different kinds of atoms, there are just a few elements from which we are organized, and even fewer that are abundant in living organisms. We shall get acquainted with some of these.
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Chemistry Concepts - 2 The Arrangement and Properties of Atoms Atoms are composed of hundreds of smaller subatomic particles. Fortunately, to understand Biology 101, we need only look at three of these basic particles, which are located in two regions of the atom: the nucleus and the surrounding electron orbitals. The "force" that holds these particles "together" forming the atom is an electrical charge (positive and negative) between subatomic particles. The nucleus of an atom contains two sub-atomic particles: protons and neutrons . A third type of particle, electrons, are found in orbitals in motion surrounding the nucleus of the atom.
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