Name ______Date ______Period ____
Homework and Test Recovery
Chapter 2: Atoms, Molecules, and Ions
Exercises: Sections 2.5, 2.6, and 2.7: The Periodic Table; Molecules and Ions
1. Locate each of the following element in the periodic table; indicate whether it is a metal (M), metalloid
(ML), or nonmetal (NM); and give the name of the element. Also, include both the IUPAC and American
System Group numbers.
Element / Type / Name / Group #IUPAC System / Group #
American System
Na
Ti
Ga
U
Pd
Se
Kr
2. The elements of group 14 (4A) show an interesting change in properties with increasing period. Give the
name and chemical symbol of each element in the group, and label it as a metal (M), metalloid (ML), or
nonmetal (NM); also, include both the IUPAC and American System Group numbers.
Atomic# / Name / Chemical
Symbol / Type / Group #
IUPAC System / Group #
American System
3. Two compounds have the same empirical formula. One substance is a gas, the other is a viscous liquid.
How is it possible for two substances with the same empirical formula to have markedly different properties?
4. Determine the molecular and empirical formulas of the following:
(a) The organic solvent benzene, which has six carbon atoms and six hydrogen atoms.
Molecular formula Empirical formula
(b) The compound silicon tetrachloride, which has a silicon atom and four chlorine atoms and is used in
the manufacture of computer chips.
Molecular formula Empirical formula
(c) The reactive substance diborane, which has two boron atoms and six hydrogen atoms.
Molecular formula Empirical formula
(d) The sugar called glucose, which has six carbon atoms, twelve hydrogen atoms, and six oxygen
atoms.
Molecular formula Empirical formula
5. How many of the indicated atoms are represented by each chemical formula:
(a) carbon atoms in C2H5COOCH3______
(b) oxygen atoms in Ca(CO3)2______
(c) hydrogen atoms in (NH4)2HPO4______
6. Write the molecular and structural formulas for the compounds represented by the following models:
C
Ball-and-Stick Models
Space-filling Models
Molecular Formula Structural Formula
(a)
(b)
(c)
(d)
7. Write the empirical formula corresponding to each of the following molecular formulas:
1
(a) S4N4 ______
(b)C7H15______
(c)C6H10O2______
(d)P4O6______
(e)C6H10F8______
(f)Si3O9______
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8. Using the periodic table, predict the charges of the ions of the following elements:
1
(a) Ba ______
(b) La ______
(c) Ga ______
(d) S ______
(e) Br______
1
1
9. The most common charge associated with silver in its compounds is 1+. Indicate the empirical formulas you
would expect for compounds formed between Ag and
(a) iodine ______(b) sulfur______(c) fluorine______
10. Predict the chemical formulas of the compounds formed by the following pairs of ions:
1
(a) Mg2+ and NO3¯______
(b) Na+ and CO32¯______
(c) Ba2+ and OH ¯______
(d) NH4+ and PO43¯______
(e) Hg22+ and ClO3¯______
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10. Which of the following are ionic (I), and which are molecular (M)?
1
(a) Sc2O3______
(b) NaI ______
(c) SCl2______
(d) Ca(NO3)2______
(e) FeCl3______
(f) LaP______
(g) CoCO3______
(h) (NH4)2SO4 ______
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11. Fill in the gaps in the following table:
Symbol
/ 75As3 –Protons / 28 / 53
Neutrons / 31 / 74 / 118
Electrons / 26 / 76
Net Charge / 1 – / 3+
Group #(American System)
1