chapter_02new_1

chapter_02new_1 - Chapter 2 Atoms, Molecules, and Ions...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
Atoms, Molecules, and Ions Chapter 2 Atoms, Molecules, and Ions
Background image of page 1

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions Atomic Theory of Matter The theory that atoms are the fundamental building blocks of matter reemerged in the early 19th century, championed by John Dalton.
Background image of page 2
Atoms, Molecules, and Ions Dalton’s Postulates 1) Each element is composed of extremely small particles called atoms . 2) All atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of all other elements . 3) Atoms of an element are not changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions. 4) Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms .
Background image of page 3

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions Law of Constant Composition Joseph Proust (1754–1826) Also known as the law of definite proportions. The elemental composition of a pure substance never varies.
Background image of page 4
Atoms, Molecules, and Ions Law of Multiple Proportions Mass ratio in one compound is related to mass ratio in another compound by a small whole number
Background image of page 5

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions Law of Conservation of Mass The total mass of substances present at the end of a chemical process is the same as the mass of substances present before the process took place.
Background image of page 6
Atoms, Molecules, and Ions The Electron Streams of negatively charged particles were found to emanate from cathode tubes. J. J. Thompson is credited with their discovery (1897). He measured the charge/mass ratio of the electron to be 1.76 × 10 8 coulombs/g.
Background image of page 7

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions Millikan Oil Drop Experiment Once the charge/mass ratio of the electron was known, determination of either the charge or the mass of an electron would yield the other. Robert Millikan (University of Chicago) determined the charge on the electron in 1909. Charge on droplets went up by an incremental amount Charge on drops changed rate of fall
Background image of page 8
Atoms, Molecules, and Ions Radioactivity : The spontaneous emission of radiation by an atom. First observed by Henri Becquerel. Also studied by Marie and Pierre Curie. Three types of radiation were discovered by Ernest Rutherford: α particles and β particles γ rays Charge Detm. e - photons He+
Background image of page 9

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions The Atom, circa 1900: “Plum pudding” model, put forward by Thompson. Positive sphere of matter with negative electrons imbedded in it.
Background image of page 10
Atoms, Molecules, and Ions Discovery of the Nucleus Ernest Rutherford shot α particles at a thin sheet of gold foil and observed the pattern of scatter of the particles.
Background image of page 11

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

View Full DocumentRight Arrow Icon
Atoms, Molecules, and Ions The Nuclear Atom Since some particles were deflected at large angles, Thompson’s model could not be correct.
Background image of page 12
Molecules, and Ions The Nuclear Atom Rutherford postulated a very small, dense nucleus with the electrons around the outside of the atom. Most of the volume of the atom is empty
Background image of page 13

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

View Full DocumentRight Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 72

chapter_02new_1 - Chapter 2 Atoms, Molecules, and Ions...

This preview shows document pages 1 - 14. Sign up to view the full document.

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