Chapter 9 Test Flashcards
Greek philosopher who said that atoms could not be divided, created or destroyed
Democritus
Greek philosopher who thought that matter is made up of fire, water, earth. and air
Aristotle
English teacher of the 1700s who stated that all mater is made of atoms that cannot be divided and that atoms combine in specific ratios
Dalton
English scientist who concluded that cathode rays are made up of negatively charged particles called electrons
Thomson
Student of Thomson who discovered that the atoms mass and positive charge are concentrated in a small area in its center
Rutherford
Scientist who discovered that the nucleus contains neutrons in addition to protons
Chadwick
Student of Rutherford who stated that electrons exist in circular orbits around the nucleus
Bohr
Explain how they find the average atomic mass of isotopes
They average the isotopes but the most common isotope is weighted more
The scanning tunnel microscope allows scientists to see what
atoms
Isotopes are atoms that have different
mass numbers
How does a neutral atom become a positive ion
by losing electrons
Who discovered the neutron
James Chadwick
Elements have a different number of
Protons
Tell what material is released in each of the following: alpha decay, beta decay, gamma decay.
Alpha: 2 protons and 2 neutrons released, the atomic number decreases by 2 Beta: releases 1 high energy electron, atomic number increases by 1 Gamma: only energy is released, no change in the atomic number
When you add the number of protons and neutrons in an atom you get the
Mass number
