Part = Writing = Covalent Formulas Write chemical formulas for the following molecular compounds: Nitrogen monoxide NO Disulfur decafluoride SF6 Nitrogen tribromide NBr3 Dinitrogen tetrahydride N2H4 Sulfur hexaiodide SI6 Carbon dioxide CO2 Phosphorus trihydride PH3 Dihydrogen sulfide H2S Phosphorus pentachloride PCl5 Disilicon octahydride Si2H6
The Correct Answer and Explanation is:
Here are the correct chemical formulas for the given molecular compounds:
- Nitrogen monoxide – NO
- Disulfur decafluoride – S₂F₁₀
- Nitrogen tribromide – NBr₃
- Dinitrogen tetrahydride – N₂H₄
- Sulfur hexaiodide – SI₆
- Carbon dioxide – CO₂
- Phosphorus trihydride – PH₃
- Dihydrogen sulfide – H₂S
- Phosphorus pentachloride – PCl₅
- Disilicon octahydride – Si₂H₈
Explanation
Writing covalent or molecular formulas involves understanding how nonmetal elements combine and using prefixes to determine the number of atoms of each element in a compound. Unlike ionic compounds, molecular compounds use Greek prefixes to indicate the number of atoms.
Prefixes like mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, and deca- are used. For example, mono- means one, di- means two, tri- means three, and so on. These prefixes are attached to the element names to show the quantity of atoms.
For Nitrogen monoxide, “mono-” indicates one oxygen, and since the nitrogen has no prefix, it implies one atom of nitrogen. This makes the formula NO. If “mono-” appears on the first element, it is often omitted, but never omitted for the second.
In Disulfur decafluoride, “di-” means two sulfur atoms, and “deca-” means ten fluorine atoms, giving the formula S₂F₁₀.
Each of the listed compounds follows this pattern. For Dinitrogen tetrahydride, “di-” indicates two nitrogen atoms and “tetra-” indicates four hydrogen atoms, giving N₂H₄.
Some elements naturally form certain molecules, like carbon dioxide, CO₂, where “di-” means two oxygen atoms.
Understanding these prefixes and the rules of naming allows chemists to correctly interpret and write chemical formulas for molecular compounds. Note that the atoms do not gain or lose electrons but rather share them in covalent bonding, and the naming is purely based on the number of atoms of each nonmetal element in the molecule.
