# Cations_and_Anions by stariya

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```									Name:___________________           Date:______________              Period: ______A or B     #______

IONS
REVIEW:
The periodic table gives you the following information for Beryllium:

4
Be
Beryllium
9.012

   The chemical symbol for Beryllium is ______

   The atomic number for Beryllium is _____.
o This means that Beryllium has ____ protons and ____ electrons.

   The atomic mass of Beryllium is ________. T
 REMEMBER: To find the mass number you round the atomic mass to the nearest whole
number. Therefore the mass number is _____.

   So the number of neutrons is calculated by taking the mass number and then subtracting the
atomic number. So the number of neutrons in Beryllium is
________ - _________ = ___________

PART A - DETERMINING THE CHARGE:

   Protons have a positive charge (p+).
Therefore, protons are represented as a positive number when determining the charge.

   Electrons have a negative charge (e-).
Therefore, electrons are represented as a negative number when determining the charge.

   Neutrons have a neutral charge (no)

To find out the charge of an individual atom, you must add the number of electrons (REMEMBER: This
will be a shown as a negative number because the charge of electrons are negative) and the number of
protons. If your result is a negative number, then the charge of the atom is negative. If your result is a
positive number, then the charge of the atom is positive. If your result is zero then the charge is neutral.

Do you need to do anything with the number of neutrons to calculate the charge? _________________
First you will review and find the mass # and number of neutrons for each atom.
Then you will calculate the charge of the atoms given below. Be sure to show your work in the
space provided near each question.

FLUORINE
Atomic # = 9             Atomic Mass 18.9984               Mass # ______________

# of Neutrons: ___________

# of Protons: _________
# of Electrons : ________

Charge: ____________

PHOSPHORUS
Atomic # = 15            Atomic Mass 30.974                Mass # ____________

# of Neutrons: ___________

# of Protons: _________
# of Electrons : ________

Charge: ____________

ZINC
Atomic # = 30            Atomic Mass 65.38                 Mass # ____________

# of Neutrons: ___________

# of Protons: _________
# of Electrons : ________

Charge: ____________

All atoms follow the pattern above.
Therefore all single atoms (not in a compound or bonded to another atom) will have a charge of __________.
PART B – IDEAL OUTER ENERGY LEVELS:
Observe the Bohr diagrams given below that show three noble gases.
REMEMBER: Noble gases are extremely unreactive elements, which are found in the last column of the
periodic table (the far right.) Bohr diagrams show ALL of the electrons of an atom and the appropriate
location of their energy levels. Scientists know that electrons do not orbit the nucleus in perfect circles as
shown on a Bohr diagrams, but this is an easy way to visually show the location of each energy level.

HELIUM                            NEON                                       ARGON

The elements shown above have “ideal” energy levels. All other elements that do not have outside
energy levels with the same number of electrons as those shown above try to do what they can do
to get to “look” like one of these three elements or one of the other noble gases.

1. How many electrons are in the first energy level (inside circle) when it is “ideal”?

2. How many electrons are in the second energy level (middle circle) when it is “ideal”?

3. How many electrons are in the third energy level (outer most circle) when it is “ideal”?

Study the Bohr Diagram of Fluorine given below:

4.   Does Fluorine have an “ideal” outer energy level?                                 Why or Why not?

5. For Fluorine to achieve “ideal” outer energy levels, how many electrons would it have to lose?

For Fluorine to achieve “ideal” outer energy levels, how many electrons would it have to gain?

6. Based on the answers you gave in #5, which would require less movement of electrons to achieve
an “ideal” outer energy level – losing electrons or gaining electrons?

7. Go back to Part A and fill in the information below for a Fluorine atom:

Number of Protons: _______        Number of Electrons: _______

Charge: _________
Now draw a Bohr diagram of Fluorine but add an extra electron on the outside energy level.

Calculate the charge of the Fluorine that you just drew in the Bohr diagram above.
REMEMBER: The number of protons DID NOT CHANGE.
Also, protons have a positive charge and electrons have a negative charge.

Number of Protons: _______          Number of Electrons: _______

Charge: _________

NOTE:         Whenever a particle has a positive or negative charge it is called an ion.
If the particle has a positive charge it is called a cation.
If the particle has a negative charge it is called a anion.

8.   What kind of ion does Fluorine form? (See the information given in question 7 if you need assistance)

Study the Bohr Diagram of Oxygen given below:

9.   Does Oxygen have an “ideal” outer energy level?                                       Why or Why not?

10. For Oxygen to achieve “ideal” outer energy levels, how many electrons would it have to lose?

For Oxygen to achieve “ideal” outer energy levels, how many electrons would it have to gain?

11. Based on the answers you gave in #10, which would require less movement of electrons to
achieve an “ideal” outer energy level – losing electrons or gaining electrons?

12. Use your periodic table to obtain the information needed and fill it in below for an Oxygen atom:

Number of Protons: _______          Number of Electrons: _______
Charge: _________
Now draw a Bohr diagram of Oxygen but add two extra electrons on the outside energy level.

Calculate the charge of the Oxygen atom that you just drew in the Bohr diagram above.
REMEMBER: The number of protons DID NOT CHANGE.
Also, protons have a positive charge and electrons have a negative charge.

Number of Protons: _______          Number of Electrons: _______

Charge: _________

NOTE:         Whenever a particle has a positive or negative charge it is called an ion.
If the particle has a positive charge it is called a cation.
If the particle has a negative charge it is called an anion.

13.   What kind of ion does Oxygen form? (See the information given in question 12 if you need assistance)

Study the Bohr Diagram of Lithium given below:

14. Does Lithium have an “ideal” outer energy level?                              Why or Why not?

15. For Lithium to achieve “ideal” outer energy levels, how many electrons would it have to lose?

For Lithium to achieve “ideal” outer energy levels, how many electrons would it have to gain?

16. Based on the answers you gave in #15, which would require less movement of electrons to
achieve an “ideal” outer energy level – losing electrons or gaining electrons?

17. Use your periodic table to obtain the information needed and fill it in below for a Lithium atom:

Number of Protons: _______          Number of Electrons: _______

Charge: _________
Now draw a Bohr diagram of Lithium but with remove the electron from the outside energy level.
NOTE: If there are no electrons on an energy level you don’t have to draw it.

Calculate the charge of the Lithium atom that you just drew in the Bohr diagram above.
REMEMBER: The number of protons DID NOT CHANGE.
Also, protons have a positive charge and electrons have a negative charge.

Number of Protons: _______          Number of Electrons: _______

Charge: _________

NOTE:          Whenever a particle has a positive or negative charge it is called an ion.
If the particle has a positive charge it is called a cation.
If the particle has a negative charge it is called an anion.

18.   What kind of ion does Lithium form? (See the information given in question 17 if you need assistance)

PART C – SUMMARY:
1.    All atoms try to have their energy levels filled with electrons just like the noble gases.

o If they have only one energy level it will be filled with ______ electrons.

o If they have two energy levels they need _____ on the first energy level and ____ on the
second energy level.

o If they have three energy levels it is considered “ideal” if they have ______ on the first
energy level, ________ on the second energy level and ________ on the third energy
level.

2. If an atom gains one or more electrons to achieve the ideal, then its charge will be negative.
Explain why it would be negative.

3. If an atom loses one or more electrons to achieve the ideal, then its charge will be positive.
Explain why it would be positive.

4. A charged particle is called an ______.

5. A positive ion is called a(n) __________. A negative ion is called a(n) ________.

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