Example #3 – Write the formula for: tin(IV) phosphide Step #1 -First symbol is Sn from the name tin and the Roman numeral IV gives +4 as tin’s charge. We write Sn Step #2 – Phosphide gives PP This compound’s formula is Sn3P4. Practice Problems – Given the Formula. Write the Name Write the correct formula for the following Type II binary ionic compounds. 1) iron(II) chloride 2) copper(1) sulfide 3) lead(IV) iodide 4) tin(II) fluoride 5) chromium(II) nitride 6) tin(II)oxide 7) chromium(III) oxide 8) gold(1) iodide 9) manganese(II) nitride 10) cobalt(III) phosphide 11) iron(III) chloride 12) copper(II) sulfide 13) lead(II) bromide 14) tin(IV) iodide 15) mercury(II) fluoride 16) tin(IV) oxide 17) manganese(III) chloride 18) chromium(II) nitride 19) gold(III) oxide 20) cobalt(II) phosphide Step #1 – the first element is nitrogen and there are two. This part of the name will be dinitrogen. Step #2 – the second element is oxygen, so “oxide” is used. Since there are five, the prefix “penta” is used Step #3 – We drop the “a” from penta and write pentoxide The correct name for the compound is dinitrogen pentoxide. Practice Problems – Given the Formula. Write the Name Write the correct name for the following binary molecular compounds. Write the correct name for 1) As.Oue 2) BO 3) BN 4) N20 5) NI 6) SF 7) XeF: 8) PCI: 9) CO 10) PCIS 11) P,0 12) S.CH: 13) ICI: 14) SO 15) P.O. 16) UF. 17) OF: page 11 of 18 18) CIO 19) SiO 20) BE Now let’s practice writing formulas for binary molecular compounds if given the name. Here are a few examples: Example #4 – write the formula for diphosphorous pentoxide. Step #1 – the first symbol is P and the subscript is 2. Step #2 – pentoxide says five oxygen’s are involved The formula of this compound is P:Os. Practice Problems – Given the Name. Write the Formula Write the correct formula for the following binary molecular compounds. 1) chlorine monoxide 2) oxygen difluoride 3) boron phosphide 4) dinitrogen monoxide page 12 of 18 5) nitrogen trifluoride 6) sulfur tetrachloride 7) xenon trioxide 8) carbon dioxide 9) diphosphorous pentoxide 10) phosphorous trichloride 11) sulfur dioxide 12) bromine pentafluoride 13) disulfur dichloride 14) boron trifluoride 15) tetraarsenic decoxide 16) silicon tetrachloride 17) krypton difluoride 18) chlorine monoxide 19) silicon dioxide 20) boron trichloride
The Correct Answer and Explanation is :
To address these practice problems, we need to work through two key types of chemical compounds: binary ionic compounds and binary molecular compounds. These compounds are named and written according to specific rules based on their type and the elements involved.
Binary Ionic Compounds
These compounds involve a metal and a non-metal, with the metal typically forming a positive ion (cation) and the non-metal forming a negative ion (anion). When naming binary ionic compounds, we follow these steps:
- Write the name of the metal (cation) using its standard name, and if the metal can have multiple charges (as in transition metals), include the Roman numeral charge in parentheses.
- Write the name of the non-metal (anion) with the “-ide” suffix (e.g., chloride, sulfide).
For example:
- Iron(II) chloride: Iron(II) is Fe²⁺, and chloride is Cl⁻. The formula is FeCl₂.
- Copper(I) sulfide: Copper(I) is Cu⁺, and sulfide is S²⁻. The formula is Cu₂S.
- Lead(IV) iodide: Lead(IV) is Pb⁴⁺, and iodide is I⁻. The formula is PbI₄.
Binary Molecular Compounds
These compounds consist of two nonmetals, and naming them follows a set of rules using prefixes to indicate the number of atoms of each element. The prefixes are as follows:
- Mono- (1), Di- (2), Tri- (3), Tetra- (4), Penta- (5), Hexa- (6), Hepta- (7), Octa- (8), Nona- (9), Deca- (10).
- The first element is named using its full name.
- The second element uses its root name plus the “-ide” suffix.
- The prefixes are used to indicate how many atoms of each element are in the compound.
For example:
- Dinitrogen pentoxide: “Dinitrogen” indicates 2 nitrogen atoms, and “pentoxide” means 5 oxygen atoms. The formula is N₂O₅.
- Oxygen difluoride: “Di-” means 2 fluorine atoms, so the formula is OF₂.
- Sulfur tetrachloride: “Tetra-” means 4 chlorine atoms, so the formula is SCl₄.
Practice Problem Solutions
1) Iron(II) chloride: FeCl₂
2) Copper(I) sulfide: Cu₂S
3) Lead(IV) iodide: PbI₄
4) Tin(II) fluoride: SnF₂
5) Chromium(II) nitride: Cr₃N₂
6) Tin(II) oxide: SnO
7) Chromium(III) oxide: Cr₂O₃
8) Gold(I) iodide: AuI
9) Manganese(II) nitride: Mn₃N₂
10) Cobalt(III) phosphide: CoP
11) Iron(III) chloride: FeCl₃
12) Copper(II) sulfide: CuS
13) Lead(II) bromide: PbBr₂
14) Tin(IV) iodide: SnI₄
15) Mercury(II) fluoride: HgF₂
16) Tin(IV) oxide: SnO₂
17) Manganese(III) chloride: MnCl₃
18) Chromium(II) nitride: Cr₃N₂
19) Gold(III) oxide: Au₂O₃
20) Cobalt(II) phosphide: Co₃P
For binary molecular compounds:
1) Chlorine monoxide: ClO
2) Oxygen difluoride: OF₂
3) Boron phosphide: BP
4) Dinitrogen monoxide: N₂O
5) Nitrogen trifluoride: NF₃
6) Sulfur tetrachloride: SCl₄
7) Xenon trioxide: XeO₃
8) Carbon dioxide: CO₂
9) Diphosphorous pentoxide: P₄O₁₀
10) Phosphorous trichloride: PCl₃
11) Sulfur dioxide: SO₂
12) Bromine pentafluoride: BrF₅
13) Disulfur dichloride: S₂Cl₂
14) Boron trifluoride: BF₃
15) Tetraarsenic decoxide: As₄O₁₀
16) Silicon tetrachloride: SiCl₄
17) Krypton difluoride: KrF₂
18) Chlorine monoxide: ClO
19) Silicon dioxide: SiO₂
20) Boron trichloride: BCl₃
This breakdown provides a comprehensive understanding of the naming conventions and formula writing for both types of compounds.