Transcript Slide 1
Physical Science The Atom Atoms – the smallest recognizable building block used to make all other substances Atom = one Element = many Atoms Atoms are so small that you can count a line of a million carbon atoms or more across your thumbnail So, if they are so small, how do we know anything about them Well, Amazing experiments by cool scientists…… that’s how Cathode Ray Tube Images from Yahoo images Development of the Atom • Joseph John Thompson - Used cathode ray tube to discover the negative charged electron and the mass to charge ratio on the electron Development of the Atom • Joseph John Thompson - Used cathode ray tube to discover the negative charged electron and the mass to charge ration on the electron • Robert Millkan - Determined the electron charge, using oil drop experiment Development of the Atom • Joseph John Thompson - Used cathode ray tube to discover the negative charged electron and the mass to charge ration on the electron • Robert Millkan - Determined the electron charge, using oil drop experiment • Dmitri Mendeleev - Father of the periodic table – predicted that his unfilled table represented undiscovered elements Mendeleev’s Periodic Table Particle charge mass symbol Alpha 2+ 4 amu a Beta 1- 1/1837 amu b Gamma 0 0 g stopped by Paper foil 1 inch lead Particle symbol mass charge Proton p+ 1.67 x10-27kg (1amu) 1+ Neutron n 1.67 x10-27kg(1amu) 0 Electron e9.11 x 10-31kg 1- position nucleus nucleus outside Atomic number The number of protons and electrons in an atom Atomic Mass The number of protons + Neutrons in an atom Isotope Atoms with the same number of protons but a different number of neutrons e e e