CAS BI 107 Chapter Notes - Chapter 2: Periodic Table, Covalent Bond, Hydrogen Bond
11 Nov 2016
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Document Summary
Chemistry = the study of matter and the changes matter undergoes. Element defined: the basic kinds or types of matter, a substance that cannot be broken down further by chemical means. Substances whose atoms have the same # of protons. 92 elements occur naturally, 25 found in living things. The 4 most important elements (>97% mass: carbon [c, oxygen [o, hydrogen [h, nitrogen [n] Atom defined: the smallest fundamental particles of matter that still retain the identity of an element. Atoms have two basic regions: nucleus, orbitals (shells) Composed of 3 smaller particles (subatomic particles: protons, electrons, neutrons. Atoms in an uncombined state have the same number of protons and electrons; therefore they are electrically neutral. Most of the mass of an atom is in the nucleus. Most of the volume is empty space occupied by orbitals. Periodic table always refers to atoms in an uncombined state. Diatomic molecules: h2, o2, n2, f2, cl2, br2, i2.
