Chapter 3 Flashcards
All atoms of a given type are ________ to each other.
similar
What 3 physical characteristics of all atoms are known with a great deal of certainty?
size, shape, and mass
Atoms are incredibly small but they differ in _____ and _______.
size and mass
If atoms can break apart, they must be made of something ______ than an atom.
smaller
___________ are small particles which serve as fundamental building blocks for all atoms.
Subatomic particles
All atoms are made up of very small particles called ______ _______.
subatomic particles
_______ have a negative charge.
Electrons
_______ have a positive charge.
Protons
______ have NO charge.
Neutrons
The subatomic particles can be distinguished from each other based on their _____ and ______.
charge and size
What is the charge associated with an electron?
negative
Why did it take so long to find the neutron?
Neutrons don’t have a formal charge
What is the overall charge of an atom?
neutral
In order for an atom to have a neutral charge, it must contain the same number of _____ and _______.
protons and electrons
Electrons travel from the ______ electrode and move toward the ______ one.
negative (cathode);
positive (anode)
Robert Millikan was able to calculate the _________ of an electron.
charge / mass ratio from the experimental data
Protons move toward the ______ electrode.
negative
Protons are approximately ____ more ______ than electrons.
1800 times more massive
What did scientists NOT KNOW about atoms and subatomic particles after the discovery of radioactivity?
They didn’t know how they were organized within the structure and they didn’t know about neutrons.
What is the calculated mass, in grams, of a proton?
1.673 x 10^-24g
Ernest Rutherford proposed that most of the mass of an atom was found where?
in the nucleus
Since the total mass of all the electrons in an atom is negligible, the mass of an atom is determined by the number of ____ and ______.
protons and neutrons
Protons and neutrons are much ______ than electrons.
heavier
According to the modern atomic model, most of the volume of an atom is ______ space.
empty