Writing Formulas for Binary Molecular Compounds
What is the ratio of the ions in carbon tetrachloride?
What is the formula for carbon tetrachloride?
1. Read and Understand
What information are you given?
The name of the compound is carbon tetrachloride.
2. Plan and Solve
List the symbols cation and anion.
Carbon is C and chloride (the chlorine ion) is Cl.
Determine the ratio of ions in the compound.
Carbon has no prefix so it is understood that there is only one carbon.
Chlorine has the prefix of tetra– which means four.
The ratio of the ions in the compound is 1 to 4.
Write the formula for carbon tetrachloride.
CCl4
3. Look Back and Check
Is your answer reasonable?
Each carbon atom loses four electrons and each chlorine atom gains one electron. So there
should be a 1 to 4 ratio of carbon ions to chloride ions.
Practice
What is the formula for…
1) diphosphorus pentoxide? __________________________________
2) sulfur hexafluoride? __________________________________
3) tetraiodine nonoxide? __________________________________
4) nitrogen trioxide? __________________________________
5) carbon tetrahydride? __________________________________
6) phosphorus trifluoride? __________________________________
7) carbon monoxide? __________________________________
8) diboron hexahydride? __________________________________
9) nitrogen tribromide? __________________________________
10) antimony tribromide? __________________________________
11) hexaboron silicide? __________________________________
12) chlorine dioxide? __________________________________
13) dinitrogen trioxide? __________________________________