BILD 1 Chapter Notes - Chapter 2: Chemical Equilibrium, Valence Electron, Radionuclide
18 Dec 2018
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Formic acid is produced by ants to ward off preys. 2. 1 matter consists of chemical elements in pure form and in combinations called compounds. Matter: anything that takes up space and has mass. Element: substance that cannot be broken down to other substances by chem reactions. Compound: substance consisting of two or more diff elements combined in a fixed ratio. Essential elements: 20-25% of elements that organisms need to survive. Oxygen, carbon, hydrogen, nitrogen 96% living matter. Calcium, phosphorus, potassium, sulfur remaining 4% Trace elements: required by organism in only small quantities. Iron: needed by all forms of life. 2. 2 an element"s properties depend on the structure of its atoms. Atom: smallest unit of matter that still retains properties of an element. Atomic nucleus: protons + neutrons; center of atom. Same elements = same # protons and # of electrons. Isotopes: diff atomic forms of same element with different number of neutrons.
