CHEM 1610 Chapter Notes - Chapter 2: Ion, Bromine, Weighted Arithmetic Mean
4 Oct 2018
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Document Summary
Law of constant composition: relative number of atoms is a constant. Law of conservation of mass: atoms present are the same before and after reaction. Alpha particle with 2+ charge: beta particle with electrons, gamma particle with radiation, plum pudding model. 1910 rutherford gold foil experiment: most particles did not get deflected, small % were highly deflected. Nuclear model: most of mass in dense nucleus, electrons circulate in open space, atoms are composed of protons, neutrons, electrons, proton 1. 6727x10-24, neutron1. 6750x10-24, electron 9. 110x10-28. Atomic symbols top is the mass number: number of protons plus neutrons bottom is the atomic number, number of protons. Add or subtract a proton to a nucleus creates a new element. Add or subtract a neutron to/from a nucleus creates an isotope of same element. Each element isotope has a different mass, but only one mass is shown in periodic table bc it is the weighted average of the mass of all isotopes.
