Question

1. ionic compounds containing transition metals are slightly different than ionic compounds containing representative - element ions, in that transition metals can have more than one possible charge. the charge on the transition - metal ion is contained in the compound name in the form of roman numerals. an example is iron(ii) sulfate. this is a compound formed from fe²⁺, and so₄²⁻. the ionic formula is therefore feso₄.

the charge on the iron ion in fecl₃, on the other hand, must be determined before we can name this compound. the process is to determine the number of negative charges in the compound to calculate the charge on each iron ion. each chloride ion has a charge of (-1), leading to a total charge of 3-. this means that the single iron ion must be 3+, leading to the name iron(iii) chloride.
cucl₂ ________________ chromium(iii) oxide __________
cos ________________ titanium(iv) nitrite __________

1. the name for a binary covalent compound is obtained by listing the name of the first non - metal elemental name, followed by the second non - metal elemental stem with the ending - ide. greek prefixes are used to denote the number of atoms for each element. mono is ignored for the first atom.

co carbon monoxide __________ sif₆ __________
no __________ pcl₃ __________
ccl₄ ____________

1. the formula for a binary covalent compound is very easy to obtain from the compound name. the first element in the name is listed using subscripts for any prefixes, and the same is done for the second element in the compound name.

dinitrogen tetroxide n₂o₄ __________ diphosphorus pentoxide __________
sulfur hexafluoride __________ carbon disulfide __________
boron trifluoride ____________

Explanation:

Step1: Determine charge for ionic compounds

For ionic compounds with transition - metals, find the charge on the transition - metal ion based on the charge of the non - metal ion. For $CuCl_2$, each $Cl^-$ has a charge of $- 1$, so two $Cl^-$ give a total negative charge of $-2$. Thus, the $Cu$ ion has a charge of $2 +$, and the name is copper(II) chloride. For $CoS$, $S^{2 -}$ has a charge of $-2$, so $Co$ has a charge of $2+$, and the name is cobalt(II) sulfide. For chromium(III) oxide, $Cr^{3+}$ and $O^{2 -}$, to balance the charges, the formula is $Cr_2O_3$. For titanium(IV) nitrite, $Ti^{4+}$ and $NO_2^-$, the formula is $Ti(NO_2)_4$.

Step2: Name binary covalent compounds

For binary covalent compounds, use Greek prefixes. For $SiF_6$, the name is silicon hexafluoride. For $NO$, the name is nitrogen monoxide. For $PCl_3$, the name is phosphorus trichloride. For $CCl_4$, the name is carbon tetrachloride.

Step3: Write formulas for binary covalent compounds

For dinitrogen tetroxide, the formula is $N_2O_4$. For diphosphorus pentoxide, the formula is $P_2O_5$. For sulfur hexafluoride, the formula is $SF_6$. For carbon disulfide, the formula is $CS_2$. For boron trifluoride, the formula is $BF_3$.

Answer:

$CuCl_2$: copper(II) chloride; $CoS$: cobalt(II) sulfide; chromium(III) oxide: $Cr_2O_3$; titanium(IV) nitrite: $Ti(NO_2)_4$; $SiF_6$: silicon hexafluoride; $NO$: nitrogen monoxide; $PCl_3$: phosphorus trichloride; $CCl_4$: carbon tetrachloride; dinitrogen tetroxide: $N_2O_4$; diphosphorus pentoxide: $P_2O_5$; sulfur hexafluoride: $SF_6$; carbon disulfide: $CS_2$; boron trifluoride: $BF_3$