5. Which of the following characteristics is
associated with electrons?
a. positive charge
b. located in the nucleus
c. mass equal to a neutron
d. negative charge
This is a good example of the need to spend time memorizing the basic
information. You need to know the properties of the subatomic particles - protons,
neutrons, and electrons. Make a table like the following and see if you can fill it out.
You need to know everything in this table!
Subatomic Particle |
Electrical Charge |
Weight or Mass |
Position in Atom |
Number of Particles |
proton |
positive |
1amu * |
nucleus |
Same for all atoms of a given element; each atom type
has a specific number of protons; the number of protons an atom has is called its atomic
number. |
neutron |
no charge |
1amu |
nucleus |
Variable in atoms of the same element; thus, all atoms
of a given element are not exactly the same; atoms of the same element with different
numbers of neutrons in their nucleus are called isotopes. |
electron |
negative |
0 |
energy levels or electron shells (2 electrons in the
first shell, 8 in the second shell, and up to 18 in the third shell) |
The number of electrons that an atom has is equal to the
number of protons (atomic number) in its nucleus. Thus an atom before it reacts is
electrically neutral. |
* amu = atomic mass units, a relative weight. These particles have so little mass
that the mass can't be evaluated in terms of grams or even micrograms. The amu is a
relative weight. Thus, protons and neutrons weigh about the same amount, and each
proton and neutron is assigned a weight of one amu. Compared to the
weight of protons and neutrons, electrons don't have any weight.