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14 Cards in this Set

  • Front
  • Back
What is an atom?
It is the smallest particle into which an element can be divided and still be the same substance.
What is a theory?
a unifying explanation for a broad range of hypotheses and observations that have been supported by testing
What are electrons and where are they found?
They are negatively charged particles found in the electron clouds or energy levels OUTSIDE the nucleus.
What is a model?
a representation of an object or system
What is a nucleus? What particles will you find inside it?
A tiny, extremely dense, positively charged region in the center of an atom.

Protons, Neutrons are found there.
Electron Clouds
The regions surrounding the nucleus where electrons are found.
the positively charge particles found in the nucleus
Atomic Mass Unit
the SI unit used to express the masses of particles in atoms
the particles found in the nucleus that have no charge and are NEUtral.
Atomic number
is equal to the number of protons in the nucleus.
atoms of the same element that have the same number of protons BUT different numbers of neutrons.
Atomic mass number
the sum of the protons and neutrons in an atom.
How do you calculate the number of neutrons in an atom?
Atomic mass number minus the atomic number
How do you calculate the number of protons and electrons in a balanced atom?
Protons=atomic number

Electrons=atomic number