Name:___________________
Unit 2 Notes: Atomic Structure
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Matter is anything that ___________________________________.
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All matter is made of ____________.
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Atoms are the ____________ _____________ of matter, sort of how
bricks are the building blocks of houses.
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Atom: ___________________________________________________
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Atoms are composed of 2 regions:
Nucleus: _____________________________________________
Electron cloud:_________________________________________
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The nucleus contains _____ of the 3 subatomic particles:
___________: positively charged subatomic particles
___________: neutrally charged subatomic particles
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The 3rd subatomic particle resides outside of the nucleus in the electron
cloud
___________: ________________________________________
____________________________________________________
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_____________ and _____________ live compacted in the tiny positively
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charged _______________ accounting for most of the _______ of the
atom.
The negatively charged _____________ are small and have a relatively
small mass but occupy a large volume of space ____________ the nucleus
In a NEUTRAL atom:
The ___________ = the ______________
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If ______ protons are present in an atom then ________ electrons are
there to balance the overall charge of the atom.
The neutrons have __ _________; therefore they do not have to equal the
number of protons or electrons
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Atomic number: this number indicates the___________ ___ _______ in
an atom
Ex: Hydrogen’s atomic number is ___
So hydrogen has ___ proton
Ex: Carbon’s atomic number is ____
So carbon has ____ protons
**The number of protons ____________ the atom.
Ex. 2 protons = He, 29 protons = Cu
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Mass number: the number of _________ and ________ in the nucleus
# of neutrons = mass # - atomic #
Or we could say that the # of protons + # of neutrons = mass #
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The electrons are equal to the ________ ___ ________
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Determine the number of subatomic particles in the following:
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Cl has a mass # of 35 and an atomic # of 17
p+ = ____, no = ____, e- = _____
are atoms that have the
same number of
protons but different
numbers of neutrons.
e mass numbers are
different because the
numbex. 126C 136C
14
6C