TRUE or FALSE
Electrons have a positive charge.
FALSE!
Electrons have a NEGATIVE
charge.
1
TRUE or FALSE
All atoms of the same element
contain the same number of
neutrons.
FALSE!
Protons are what determine an
element is. Neutrons can change in
isotopes.
2
TRUE or FALSE
Protons have no electrical charge.
FALSE!
Neutrons have no electrical
charge.
Protons have a positive charge.
3
TRUE or FALSE
The atomic number of an element is the
number of protons and neutrons in the
nucleus.
FALSE!
The mass number of an element
is the number of protons and
neutrons in the nucleus.
4
TRUE or FALSE
The mass number is an average of the
masses of all naturally occurring
isotopes of an element.
FALSE!
The atomic mass is an average of
the masses of all naturally
occurring isotopes of an element.
5
The discovery of which particle
proved that the atom is not
indivisable?
A.
B.
C.
D.
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Proton
Neutron
Electron
Nucleus
How many protons does an atom
with an atomic number of 23 and a
mass number of 51 have?
A.
B.
C.
D.
23
28
51
74
Hint: Atomic Number = Number of Protons
7
In Rutherford’s gold – foil experiment, Rutherford
concluded that the atom is mostly empty space with a
small, massive, positively charged center because:
A.Most of the particles
passed straight through
the foil
B.Some particles were
slightly deflected
C.A few particles bounced
straight back
D.All of the above
8
Which of the following determines
the identity of an element?
A. Atomic Number
B. Mass Number
C. Atomic Mass
D. Overall Charge
9
Isotopes exist because atoms of the
same element can have different
numbers of
A. Protons
B. Neutrons
C. Electrons
D. None of the Above
10
What force holds electrons in atoms?
Electromagnetic force. The proton
is positive and the electron is
negative , so they are attracted to
each other.
11
In two or three sentences describe
Thomson’s plum pudding theory.
Thomson proposed that electrons were
located throughout an atom like plums in a
pudding. .
12
Caluculate the atomic mass of
gallium, which consists of 60%
gallium – 69, 40% gallium – 71.
.60 x 69 = 41.4
+ .40 x 71 = 28.4
69.8
13
Calculate the number of protons, neutrons,
and electrons in an atom of zinconium-90 that
has no overall charge and an atomic number
of 40.
Atomic Number = Number of Protons
Protons = 40
Atomic Weight = Protons + Neutrons
Neutrons = Atomic Weight – Protons
50
=
90
-
40
Electrons = 40
(Same as Protons, since no overall charge)
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ATOM
Positive (+)
Negative (-)
Proton
Electron
Neutron
Neutral (=)
Atomic
Number
Atomic # = # of Protons
Mass
Number
Isotopes
Mass # = Protons + Neutrons
Nucleus
15
Nucleus contains
protons and neutrons.
Isotopes have same number
of protons, different number
of neutrons.
Particle accelerators, such as the Hadron Collider, are
devices that speed up charged particles in order to smash
them together. Scientist use these devices to make atoms.
How can scientists determine whether the atoms formed
are a new element or a new isotope of a known element?
If the number of protons stays the same, but number of
neutrons changes, you would have a new isotope.
If the number of protons changes, you would have split the
atom into a new element.
http://www.youtube.com/watch?v=qQNpucos9wc
http://www.youtube.com/watch?v=RIg1Vh7uPyw&list=TL9l
iUotc3avVG69w_AB1a0zk9sCfDLWVc&safe=active
16
John Dalton made a number of
statements about atoms that are now
known to be incorrect. Why do you think
atomic theory is still found in science
textbooks?
Dalton’s atomic theory was the first one
based on experimental evidence. It helps
show how a theory develops as new
information is discovered.
17
If scientists had tried to repeat
Thomson’s experiment and found
that they could not, would Thomson’s
conclusion still have been valid?
No, the results of an experiment
must be repeatable to be
18
considered valid.
Completed On Board
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Completed On Board
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Completed On Board
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