userdata-paziras-Chem101-Chap_02A

Vi nucleus locatedatthecenteroftheatom

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Unformatted text preview: a particular type of radioactive rays (Alpha rays) through thin metallic foils · Alpha (a) rays consist of a stream of particles (a particles) which: Ø are positively charged Ø are relatively heavy (four times as heavy as the H atom) OBSERVATIONS INTERPRETATIOINS · Most of the a­particles pass through · The gold atom is mostly occupied by lightweight electrons that the gold foil. cannot deflect the a­partilces. · A very small part of the atom is dense (contains most of its mass) · A few a­particles (1 in 8000) were and is positively charged. scattered at large angles and sometimes deflected back. 6 Chemistry 101 Chapter 2 ATOMIC MODEL Conclusion: · The nuclear model of the atom contains a nucleus and electrons surrounding them. · · · · · · VI. NUCLEUS Located at the center of the atom Contains all the protons Is positively charged Contains most of the mass of the atom Is very small Is very dense ELECTRONS · Are located outside the nucleus · Are negatively charged · Have negligible mass · Occupy most of the volume of the atom The Discovery of the Neutron · James Chadwick discovered in 1932 that the atom contains a third subatomic particle called neutron. · The neutron: Ø is located in the nucleus Ø is electrically neutral Ø has about the same mass as the proton Properties of Subatomic Particles Particle Relative Mass Electr...
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This document was uploaded on 03/18/2014 for the course CHEM 101 at Los Angeles Mission College.

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