1. For the following binary compounds:

Midterm Exam 2. Practice problems.

1. For the following binary compounds:

a) Sort compounds on two groups –
ionic compounds and molecular compounds (compounds with covalent bonding)

b) Provide formulas for both groups (remember: there are different rules for naming ionic and covalent compounds)

sodium iodide _____________________________________

magnesium oxide _____________________________________

silicon tetrachloride _____________________________________

sulfur dioxide _____________________________________

diphosphorus pentoxide _____________________________________

calcium fluoride _____________________________________

lithium oxide _____________________________________

carbon tetrafluoride _____________________________________

2. Provide names for the following compounds:

a) Ionic

KI _____________________________________________

CaO _____________________________________________

MgBr2 _____________________________________________

Na2O _____________________________________________

b) molecular (covalent)

SF6 _____________________________________________

P2O5 _____________________________________________

NO3 _____________________________________________

N2O5 _____________________________________________

3. Complete following reactions and:

a) Use your knowledge of octet rule to find out the formula of the product. Indicate the charge on each ion (it will help you to decide what subscripts you need for each element).

b) Balance the reaction.

Na + O2Φ

K2O + H2O Φ

Ca + O2Φ

MgO + H2O Φ

4. Consider the reaction:

2S + 3O2Φ 2SO3

Following questions are independent from each other
a)How many moles of SO3 will be formed if there are 2.3 moles of O2 and sulfur is present in excess?

b) How many moles of each reactant (S and O2) do you need to get 6 moles of SO3?

c) How many grams of SO3 will be formed from 41g of S if oxygen is in excess?

d) This reaction was performed with 64 g of S and 64 g of O2.

d1)What was the limiting reactant in this case?

d2)What was the theoretical yield?

d3)What was the percent yield if there were 60 g of SO3 collected?

5.Draw a Lewis structure for the molecule of water (H2O), the molecule of methane(CH4), and the molecule of ammonia (NH3). Remember to obey the octet rule. Mark lone pairs on the Lewis structure.

6. Write the reaction of oxidation of Na by Cl using a Lewis structure

Na + Cl Φ NaCl

7. True or false:
a) Covalent bondinginvolves the transfer of valence electrons from one atom to another atom
b) in the compounds with ionic bonding elements hold together by Coulombic force.
c)An ionic bond is formed when two atoms share one or more pairs of electrons.
d) When atoms share two electron pairs it is called the double bond.
e) The valence electrons which donÈt participate in the covalent bond are called the lone pairs.

9. For the following elements : Na, F, Mg, S

a) draw the Lewis structure for each element and determine how many electrons should be gained or lost according to the octet rule.

d) For each element indicate what kind of ion is formed. (Hint: how do we call a negatively charged ion? a positively charged ion?) Indicate the charge of the ion.

10. True or false:

a) Ionization energy is the energy required to remove one electron from the atom.

b) the atomic radius decreasing when going down a group in the periodic table.

c) the elements of the groupVII in the periodic table are metals

11. Write the formulas of the following compounds.

Aluminum sulfate _________________________________

Sodium carbonate _________________________________

Ammonium hydroxide _________________________________

Potassium phosphate _________________________________

12. Write the names of the following compounds.

K2CO3 __________________________________

NaOH __________________________________

KNO3 __________________________________

MgSO4 __________________________________