CHEM 1A03 Study Guide - Midterm Guide: Subatomic Particle, Empirical Evidence, Rutherford Model

• School: McMaster University
• Department: Chemistry
• Course: CHEM 1A03
• Professor: David Brock

Document Summary

Law of definite proportions law of conservation of mass. Matter is composed of indestructible, indivisible atoms, which are identical for one element, but different from other elements. Matter is composed of atoms that contain electrons embedded in positive material. The kind of element is characterised by the number of electrons in the atom. An atom is composed of a very tiny nucleus, which contains positive charges and most of the mass of the atom. Very small negative electrons occupy most of the volume. The existence of neutral particles called neutrons in the nucleus of atoms was theorized. An atom is made up of an equal number of negatively charged electrons and positively charged protons. Most of the mass of the atom and all of its positive charge is contained in a tiny core region called the nucleus. The nucleus contains protons and neutrons that have approximately the same mass. The number of protons is called the atomic number (z).