Multiple Choice

1. The atomic number of an element is equal to
A. the number of protons and neutrons in an atom of the element.
B. the number of neutrons in an atom of the element.
C. the number of protons in an atom of the element.
D. the number of electrons in an ion of the element.

2. If the element Sodium has an atomic number of 11, and mass number of 23, then the number of neutrons found in the nucleus is equal to

3. An atom of the element X contains 8 protons and 10 neutrons. The atomic number of element X is

4. Which of the following represents a compound?

5. An example of an ionic compound is

6. An example of a molecular compound is

7. A stable element that would not form ions is

8. An example of a polyatomic ion is

9. The total number of atoms in the formula of silver sulfate - Ag₂SO₄ is

10. If the hydroxide of an element is X(OH)₂, the charge on a single ion of X is:

11. When metal atoms form ions they

A.  lose protons      B.  gain protons      C.  lose electrons    D.  gain electrons

12. The elements of the periodic table may be divided into two main sections - metals and non-metals.  Which of the following is a non-metal.

A.  Cu                     B.  Al                      C.  Pb                      D.  Cl

Short Answer.

1. Define the following – Atomic Number, Mass number, Isotope, element and compound.
   
   
2. State the Law of Constant Mass.
   
   
3. Explain the difference between an ionic compound and a molecular compound.
   
   
4. Explain the difference between and ionic bond and a covalent bond.
   
   
5. Balance the following equations.

   Al + O2—> Al 2 O 3

   Mg + H 2 O —> MgO + H 2

   Fe + O 2 —> Fe 2 O3

   CO + O2 —> CO2

   CO2 + C —> CO

   SO2 + O2 —> SO3

   PbS + O2—> PbO + SO2

   Zn + H2SO4 —> ZnSO4 + H2

   Cu + HNO3 —> Cu(NO3)2 + NO2 + H2O

   
   
6. Write chemical formulae for the following ionic compounds. (You will need to use the table of ions in your booklet).

   Sodium fluoride	calcium chloride
   potassium carbonate	zinc hydroxide
   copper (II) nitrate	magnesium phosphate
   iron(III) hydroxide	aluminium sulfate
   magnesium sulfate	sodium hydrogen carbonate.

   
   
7. Write names for the following ionic compounds.

   MgCO3	Na2SO4	Ag2SO4
   Pb(NO3)2	Fe(OH)2	FeO
   Fe2O3	ZnSO4	PbO2
   Li2SO3	Ca(CH3COO)2	AgI
   Al3(PO4)2	NH4NO3	Ca(HCO3)2

   
   
8. Write chemical formulae for the following molecular compounds.

   Carbon dioxide	Phosphorous trichloride
   sulfur trioxide	dintrogen pentoxide
   hydrogen chloride	boron trifluoride

   
   
9. Write names for the following molecular compounds.

   PCl5	SO2
   N2O3	CS2

   
   
10. Identify which of the following is an ionic compound or a molecular compound.

    CuCl2	SO2	P2O5	CaCO3
    NO2	NH4NO3	ZnSO4	PbSO4

    
    
11. Write chemical formulae for the following. [Remember; for pure metals, the formula is simply the symbol in the Periodic Table; for compounds you must refer to the table of ions if the compound is ionic. for elements of non-metals – many of these exist as two atom molecules (i.e diatomic ). You should now know the formulae of the common acids.]

zinc	hydrochloric acid	copper carbonate
magnesium	nitrogen trichloride	iron
sulfuric acid	zinc nitrate	nitric acid
oxygen	hydrogen	water



12. Convert the following word equations to balanced chemical equations.

    Aluminium + oxygen gives aluminium oxide

    Carbon + Copper oxide gives copper + carbon dioxide

    Sodium + water gives sodium hydroxide + hydrogen

    Potassium hydrogen carbonate gives potassium carbonate + carbon dioxide + water

    Calcium carbonate gives calcium oxide + carbon dioxide

    Magnesium + chlorine (Cl2) gives magnesium chloride

    Sulfur trioxide + water gives sulfuric acid.

    Magnesium chloride + silver nitrate gives silver chloride + magnesium nitrate

    Copper + nitric acid gives copper nitrate + nitrogen dioxide + water

    
    
13. Use the law of constant mass to answer the following questions.
    (a) What mass of oxygen is used when 4.8 g of magnesium is burnt to form 8 g of magnesium oxide?

    2 Mg + O2 —>2 MgO

    
    (b) When sugar (C₆H₂₂O₁₁) ferments in the presence of yeast, alcohol (C₂H₅OH) is formed. What mass of alcohol can be produced if 34.2 g of sugar and 1.8 g of water react releasing 17.6 g of carbon dioxide?

    C12H22O11 + H2O —>4 C2H5OH + 4 CO2

   Revision notes prepared byMrs J. Ariotti