Name ___________________________________
Date ____________________________________
Handout
Atomic Structure
I. What is an atom?
Atom:_________________________________________________________
______________________________________________________________
First proposed by _____________________.
II. Atomic Structure
Atoms are composed of 2 regions:
_____________: the center of the atom that contains the mass of the atom
________________ ______________ : the region that surrounds the nucleus that contains
most of the space in the atom
____________
____________
III. What’s in the nucleus?
The nucleus contains 2 of the 3 subatomic particles.
____________: positively charged subatomic particles
____________: neutrally charged subatomic particles
IV. What’s in the electron cloud?
The ________ subatomic particle resides outside of the nucleus in the __________
__________.
Electron: the ____________ particle with a __________ charge and relatively no
__________.
V. How do these particles interact?
Protons and neutrons live compacted in the tiny _______ charged nucleus accounting for all
of the ________ of the atom.
The negatively charged _____________ are small and have relatively no mass but occupy a
large _____________ of space outside of the nucleus.
VI. How do the subatomic particles balance each other?
In an atom: ________________ = __________________
If ______ protons are present in an atom then _______ electrons are there to balance the
overall charge of the atom—atoms are _______________.
The neutrons have _____ charge therefore they do not have to equal the number of protons or
electrons.
VII. How do we know the number of subatomic particles in an atom?
Atomic number: indicates the number of ___________ in an atom.
Ex: hydrogen’s atomic number is 1, so hydrogen has _______ proton.
Ex: carbon’s atomic number is ______, so carbon has _____ protons.
**The number of ___________ identifies the atom
2 p = ________
29 p = _______
VIII. How do we know the number of subatomic particles in an atom?
Atomic ______________: the number of protons and neutrons in the nucleus.
Ex: hydrogen can have a mass of ________.
Since it has 1 proton, it must have 2 neutrons.
**number of neutrons = atomic ________ - ________ #
IX. Determining the number of protons and neutrons:
Li has an atomic mass of 7 and an atomic number of 3
Protons = 3 ( same as the __________ #)
Neutrons = 7 – 3 = 4 (__________ # - _________ #)
Ne has an atomic mass of 20 and an atomic number of 10.
Protons = _______
Neutrons = ______
X. What about the electrons?
The electrons are equal to the number of ___________.
So ____ = ____ = __________ number
Ex: He has a mass number of 4 and an atomic number of 2
p = ______ n = _______ e-= ______
XI. Determine the number of subatomic particles in the following:
Cl has a mass number of 35 and an atomic number of 17
P = ______ n = _______
e- = ______
K has a mass number of 39 and an atomic number of 19.
P = ______ n = _______
e- = ______
XII. How exactly are the particles arranged?
Bohr Model of the atom:
The 4th ring and
up hold _____.
____________
____________
____________
The 3rd ring
holds _____.
The 1st ring holds
______.
The 2nd ring
holds _____.
XIII.
What does carbon look like?
Mass # __________
Atomic # ________
6 p and 6 n live
in the nucleus
p = ______
n = _________
e- = _________