Ch 4: Atomic Theory & Atomic Structure Flashcards
What did Democritus think about atoms?
Indivisible, indestructible, and made up matter.
What did Dalton do to Democritus’ ideas?
Transformed the ideas into a scientific theory.
What three laws led to Dalton’s atomic theory?
- Law of Definite Proportion
- Law of Conservation of Mass
- Law of Multiple Proportions
Dalton’s atomic theory: all ______ is made up of _____; atoms are ______________.
matter
atoms
indestructible
Dalton’s atomic theory: all atoms of a particular _______ are _________ to each other and _________ from atoms of other elements.
element
identical
different
Dalton’s atomic theory: atoms are rearranged in a ________ reaction.
chemical
Dalton’s atomic theory: _________ are formed when two or more _________ kinds of atoms join together.
compounds
different
How are atoms observed?
Using instruments such as scanning tunneling microscopes.
What are the three types of subatomic particles?
Electrons, protons, and neutrons.
Who discovered elections using cathode ray tube experiments?
JJ Thomson
Whose experiments were to find the quantity of charge carried by an electron?
Robert A. Millikan
Who discovered protons?
Eugen Goldstein
Who confirmed the existence of neutrons?
James Chadwick
What experiment tested to see whether protons/elections were arranged or randomized?
Rutherford’s Gold-Foil Experiment
The Rutherford atomic model: the atom is mostly _____. Most of the ____ is in a very small region at the center.
empty
mass
The Rutherford atomic model: the protons and neutrons are located at the _______.
nucleus
The Rutherford atomic model: the electrons are distributed ______ the nucleus and occupy almost all the ______ of the atom.
around
volume
Elements are different because they contain different numbers of _______.
protons
The number of neutrons in an atom is the difference between the ____ ______ and ______ ______.
mass number
atomic number
Because isotopes of an element have different numbers of neutrons, they also have different ____ _______.
mass numbers
How does one calculate the atomic mass of a number?
Multiply the mass of each isotope by its natural abundance, expressed as a decimal, and then add the products.
To calculate the atomic mass of a number, what do you need to know?
The number of stable isotopes of the element, the mass of each isotope, and the natural percent abundance of each isotope.
What does the Periodic Table allow you to do?
Easily compare the properties of one element (or a group of elements) to another element (or groups of elements).
