CHEM 110 Chapter 2 3 4 Atoms Chemical Compounds and Chemical Reactions Smart Notes

CHEM 110 Chapter 2 3 4 Atoms Chemical Compounds and Chemical Reactions Smart Notes

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 2, 3, 4, Smart Notes CHEM 110 Friday, September 09, 2011 CHEM 110 Chapter 2, 3, 4 Smart Notes Chapter 2: Atoms and the Atomic Theory o Early Chemical discoveries and the Atomic Theory Law of Conservation of Mass The total mass of substances present after a chemical reaction is the same as the total mass of substances Law of Constant Composition All samples of a compound have the same composition- the same proportions by mass of the constituent elements. Dalton’s Atomic Theory The 3 Assumptions of this Theory o Each chemical element is composed of minute, indivisible particles called atoms. Atoms can be neither created nor destroyed during a chemical change. o All atoms of an element are alike in mass (weight) and other properties but the atoms of one element are different from those of all other elements. o In each of their compounds, different elements combine in a simple numerical ratio, for example, one atom of A to one of B (AB), or one atom of A to two of B. The Law of Multiple Proportions o If two elements form more than a single compounds, the masses of one element combined with a fixed mass of the second are in the ratio of small whole numbers. o Electrons and other discoveries in Atomic Physics
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 2, 3, 4, Smart Notes CHEM 110 Friday, September 09, 2011 The Discovery of Electrons
Background image of page 2
Chapter 2, 3, 4, Smart Notes CHEM 110 Friday, September 09, 2011 In 1897, by the Method outlined in 2-7(c) above, J. J. Thomson established the ratio of mass ( m) to electric charge ( e) for cathode rays, that is, m/e . Also, Thomson concluded that cathode rays are negatively charged fundamental particles of matter found in all atoms. Cathode rays subsequently became known as electrons .
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chapter 2, 3, 4, Smart Notes CHEM 110 Friday, September 09, 2011
Background image of page 4
Chapter 2, 3, 4, Smart Notes CHEM 110 Friday, September 09, 2011 Oil-Drop Experiment Robert Millikan was able to find the electron charge e through a series of oil-drop experiments. The currently accepted value of the electron charge e, expressed in coulombs to five significant figures is ± ²³´´µ¶µ ³ · ¸ ¹ . By combining this value with an accurate value of the mass- to-charge ratio for an electron, we find that the mass of an electron is ¸± ³¸ºµ¶µ ³ ·´» Radioactivity Ernest Rutherford identified two types of radiation from radioactive materials, alpha, and beta. o Alpha particles carry two fundamental units of positive charge and have essentially the same mass as helium atoms (H ¼ ½¾ ions). o Beta particles are negatively charged particles produced by changes occurring within the nuclei of radioactive atoms and have the same properties of electrons. o
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/27/2011 for the course SCIENCE 110 taught by Professor Irene during the Fall '10 term at McGill.

Page1 / 24

CHEM 110 Chapter 2 3 4 Atoms Chemical Compounds and Chemical Reactions Smart Notes

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online