Last modified: Wed 12/31/1969 06:00:00 pm ACA Page

Oklahoma State University

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.


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1. If the formula of a compound contains a metal and a nonmetal element that compound is classified as an ionic compound. Ionic compounds contain cations and anions. In the periodic table above Group VIIIA elements are called the Noble gases. The elements in this group are relatively inert (unreactive) gases. For reasons we will discuss later in the semester, elements near a Group VIIIA element will lose (metals) or gain (nonmetals) electrons when in a compound to acquire the same number of electrons as their nearest noble gas.

For example, the formula of the ionic compound containing magnesium and bromine can be determined the following way. Magnesium (Z = 12) will lose two electrons when it combines with other elements so it has the same number of electrons as neon. The formula of the magnesium cation is Mg2+. Similarly, bromine (Z = 35) will gain one electron when it combines with a metallic element to have the same number of electrons as krypton. The formula of the bromide anion is Br–. The formula of the resulting compound containing magnesium and bromine is MgBr2. This formula results because we need two bromide anions (-1 charge) to balance the magnesium cation (+2 charge). See the table below;

Metal

Atomic # (Z)

# electrons lost

formula of the cation

Nonmetal

Atomic # (Z)

# electrons gained

formula of anion

formula of compound

Mg

12

2

Mg2+

Br

35

1

Br-1

MgBr2

 

Following the same logic, determine the formula for the ionic compound that contains potassium and oxygen.

Metal

Atomic # (Z)

# electrons lost

formula of the cation

Nonmetal

Atomic # (Z)

# electrons gained

formula of anion

formula of compound

K

O

Write the formula and the name of the compound containing the following elements. (NOTE: Input fields can not correctly display subscripts or superscripts. So the formula H2O can only be entered as H2O.)

Elements

Formula

Name

Mg and O

K and N

N and Br

 

2. Predict the product(s) for each of the following reactions. Be sure to include the phase of the product(s).

a) C(s) + O2(g) ---->

b) Na(s) + H2O(l) ----> (Here is a video of this reaction. Here is another video of the reaction that will provide information about the products of the reaction.)

c) Al(s) + Cl2(g) ----> (We did see a video of this reaction (Assignment Page Week 1, Thursday's class under the Movies link).)

3. For each of the following compounds indicate if it is ionic or covalent, and provide its name.

Formula

Ionic/Covalent

Name

a) Cl2O7

b) Fe2(SO4)3

c) (NH4)3PO4

d) Pb(C2H3O2)2

4. Two isotopes of silver are known to exist in nature. 107Ag has a mass of 106.99051 u and represents 51.85% of naturally occurring silver. Calculate the mass of the other isotope of silver. (HINT: You will need the average atomic mass of silver from a periodic table.) u

5. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

6. If there is one question you would like to have answered in lecture, what would that question be?