BIOL 101 Chapter Notes - Chapter 2: Radiometric Dating, Atomic Nucleus, Atomic Mass
26 Sep 2016
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Matter= anything that has mass and takes up space. Element= substance that can"t be broken down to other substances by chemical reactions. Compound= substance consisting of 2+ elements in fixed ratios. 20-25% of elements are essential elements that an organism needs to live a healthy life and reproduce. Humans need 25 elements, plants need 17. O, h, c, and n make up 96% of living matter. Trace elements= those required in only minute quantities: fe is a trace element needed by all life forms. Some species have become adapted to enviros containing toxic elements: ex. Most plants can"t survive in soil that forms from serpentine rock, but a small number of plant species have adapted. Atom= smallest unit of matter that still retains the properties of an element. Subatomic particles= small parts that atoms are composed of: protons, neutrons, electrons. Atomic nucleus= core that contains densely packed protons and neutrons. Electrons from cloud of negative charge around nucleus.
