Today’s Review
Q. 1. What is an ion?
A. 1. Positively or negatively charged atom
Q. 2. Where are cations and anions found?
A. 2. Cations (Left), Anions (Right)
Q. 3. What determines the charge of an ion?
A. 3. The number of valence electrons
Q. 5. What is the electron configuration for Cd?
A. 5. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10
Q. 6. Write the formula unit for BaCl2
A. 6. Ba^2+ + Cl^1Answers to 7.1 Quiz
1. A cation is a positively charged ion
2. An anion is a negatively charged ion
3. The group number indicates how many valence electrons there are
4. The period number is the whole number for 3s^2
5. Cations are positively charged ions
6. Anions are negatively charged ions
7. Write the electron configuration for Sc (1s^2 2s^2 2p^6 3s^2
3p^6 3d^1 4s^2)
8.a. Write the electron configuration for the calcium ion
(1s^2 2s^2 2p^6 3s^2 3p^6)
b. Argon has the same electron configuration as the calcium ion
9. Draw the dot diagram for Aluminum (Cannot be depicted in this
document.) To draw this, write the symbol for Aluminum (Al) and
imagine the symbol is surrounded by a box. Since aluminum is in
group 3A, draw 3 electrons around it,(one on each side of the
imaginary box. When drawing electron dot diagrams, start on the
right-hand side of the element / ion symbol and place one dot on each
side until you have added the appropriate number of electrons (dots)
that the element or ion should have. If it is an ion, then you will also
include the charge and number of electrons added / subtracted as a
superscript on the right-hand side of the element)
10. Draw the dot diagram for the nitrogen ion. (Cannot be depicted in
this document.) To draw this, write the symbol for Nitrogen (N) and
imagine the symbol is surrounded by a box. Since nitrogen is in group
5A, draw 5 electrons around it,(one on each side of the imaginary
box). Since it is an ion, that means it has 3 additional dots (totaling 8
dots). When drawing electron dot diagrams, start on the right-hand
side of the element / ion symbol and place one dot on each side until
you have added the appropriate number of electrons (dots) that the
element or ion should have. If it is an ion, then you will also include
the charge and number of electrons added / subtracted as a
superscript on the right-hand side of the element)
Bonus (number 11). Explain the octet rule, relate it to noble gases,
and relate it to the dot diagram: The octet rule states that all elements
want to fill their valence shell (outermost shell). To do this, elements
either give up electrons (thus becoming cations) or gain electrons
(thus becoming anions). To fill an element’s outermost shell it must
have 8 electrons in that shell. An atom will lose electrons if it has 3 or
less electrons naturally in its valence shell, while if it has 5 or more
electrons it will gain the additional electrons it needs to have 8
electrons in its valence shell. Noble gases have a full valence shell and
are located in group 8A of the periodic table of elements. Electron dot
diagrams are used to show how many electrons are in the valence
shell of the electron. If it is an ion, then it will have the additional
electrons (all represented as dots) and the appropriate charge for the
ion, (Depending on how many electrons it has gained or lost).
Answers to 7.2 and 7.3 Quiz
1. Ionic Bonds are electrically neutral, which means they have no
charge
2. Gold is an example of a face centered cubic arrangement of
atoms.
3. Copper has a body centered cubic arrangement of atoms
4. Malleable means it can be shaped
5. Ductile means it can be pulled through a wire
6. Zinc’s atoms are arranged in a hexagonal closed packed
7. Sodium and oxygen combine. Their chemical formula is Na2O
(choice C)
8. Which of these is not listed in your book as an advantage of
alloys? (Answer = C)
a. Higher melting points
b. Conducts electricity better
c. Higher Freezing Point
d. Has both qualities of combining elements
9. K4S2 is the most reduced chemical formula for potassium (True
or False)? (Answer = False, correct would be K2S)
10.
Fluorine and chlorine can combine to form an ionic
compound (True or False)? (Answer = False, correct would be that
they do not combine for form an ionic compound.)
Bonus: Write the full formula for MgBr2
Answer: Mg2+ + Br1-  MgBr2