NSCI 1321 Lecture Notes - Lecture 3: Cathode Ray, Atomic Number, Nucleon
25 Dec 2016
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Postulates of dalto(cid:374)"s ato(cid:373)ic theory the (cid:373)ai(cid:374) poi(cid:374)ts of dalto(cid:374)"s ato(cid:373)ic theory, a(cid:374) explanation of the structure of matter in terms of different combinations of very small particles, are given by the following postulates: All matter is composed of indivisible atoms. An atom is an extremely small particle of matter that retains its identity during chemical reactions. An element is a type of matter composed of only one kind of atom, each atom of a given kind having the same properties. Thus, the atoms of a given element have a characteristic mass. A compound is a type of matter composed of atoms of two or more elements chemically combined in fixed proportions. The relative numbers of any two kinds of atoms in a compound occur in simple ratios. Water, for example, a compound of the elements hydrogen and oxygen, consists of hydrogen and oxygen atoms in the ratio of 2 to 1.
