Page 112 - Theory and Problems of BEGINNING CHEMISTRY

CHAP. 6] INORGANIC NOMENCLATURE 101

Ans. In each case, the answer is CaS. Part (b) gives the ions and their changes and so is perhaps easiest to answer.
Part (a) gives the elements, so it is necessary to know that periodic group IIA elements always form 2+ ions
in all their compounds and that sulfur forms a 2– ion in its compounds with metals. It is also necessary to
remember that the metal is named first. In part (c), the fact that there is only one compound of these two
elements is reinforced by the fact that the calcium is stated with no Roman numeral, and that sulfide is a
specific ion with a specific(2–) charge.

6.61. Name (a)Cu 2 O and (b) CuO.
Ans. (a) Copper(I) oxide (b) Copper(II) oxide.

−
6.62. Distinguish between ClO 2 and ClO 2 .
−
Ans. ClO 2 is a compound, and ClO 2 is an ion—part of a compound.
6.63. Use the periodic table relationships to write formulas for (a) the selenate ion and (b) the arsenate ion.
Ans. Selenium is below sulfur in the periodic table, and arsenic is below phosphorus. We write formulas analogous
2− 3−
to those for sulfate and phosphate: (a) SeO 4 and (b) AsO 4 .
6.64. Complete the following table by writing the formula of the compound formed by the cation at the left and the anion
at the top. NH 4 Cl is given as an example.
Cl − ClO − ClO 2 − SO 3 2− PO 4 3−

+
NH 4 NH 4 Cl
K +
Ba 2+
Al 3+

Ans. Cl − ClO − ClO 2 − SO 3 2− PO 4 3−

+
NH 4 NH 4 Cl NH 4 ClO NH 4 ClO 2 (NH 4 ) 2 SO 3 (NH 4 ) 3 PO 4
K + KCl KClO KClO 2 K 2 SO 3 K 3 PO 4
Ba 2+ BaCl 2 Ba(ClO) 2 Ba(ClO 2 ) 2 BaSO 3 Ba 3 (PO 4 ) 2
Al 3+ AlCl 3 Al(ClO) 3 Al(ClO 2 ) 3 Al 2 (SO 3 ) 3 AlPO 4
6.65. From the data of Table 6-4, determine which charge is most common for first transition series elements (those
elements in period 4 among the transition groups).
Ans. The 2+ charge is seen to be most common, occurring with every element in the first transition series that is
listed. (Only Sc has no 2+ ion.)

6.66. Name the compounds of Problem 6.64.

Ans. Cl − ClO − ClO 2 − SO 3 2− PO 4 3−
+
NH 4 Ammonium Ammonium Ammonium Ammonium Ammonium
chloride hypochlorite chlorite sulfite phosphate
K + Potassium Potassium Potassium Potassium Potassium
chloride hypochlorite chlorite sulfite phosphate
Ba 2+ Barium Barium Barium Barium Barium
chloride hypochlorite chlorite sulfite phosphate
Al 3+ Aluminum Aluminum Aluminum Aluminum Aluminum
chloride hypochlorite chlorite sulfite phosphate