Prefixes from 1-10: Mono, Di, Tri, Tetra, Penta, Hexa, Hepta, Octa, Nona, Deca Covalent Compound Name (3 points each) Formula P401 CzN N2Hg Please name the following ionic compounds, use the rules below as a guide = help Step 1) Say the name of the CATION (the first part of the formula): Step 2) Say the name of the ANION and replace the ending with “ide”. Hint: If a polyatomic ion is used, DO NOT change the ending REMEMBER to check to see if the compound needs a roman numeral using the chart on the back of your periodic table or in the slideshow: If the compound needs a Roman Numeral: Step 1) Determine the charge of the ANION. Step 2) Determine the charge needed on the CATION to make the compound neutral Step 3) Place the roman numeral, equal to the charge of the CATION, in the name of the compound Formula Ionic Compound Name (3 points each) V2O5 Ba3(PO4)2
The Correct Answer and Explanation is:
Covalent Compounds (Use prefixes)
Prefixes 1–10:
Mono (1), Di (2), Tri (3), Tetra (4), Penta (5), Hexa (6), Hepta (7), Octa (8), Nona (9), Deca (10)
1. P₄O₁
→ Tetraphosphorus monoxide
2. C₂N
→ Dicarbon mononitride
3. N₂Hg
→ Dinitrogen monomercury
Ionic Compounds (Use Roman numerals if needed)
4. V₂O₅
Step 1: Cation = Vanadium (V)
Step 2: Anion = Oxygen → Oxide
Step 3: Determine oxidation state:
- O has a charge of -2.
- 5 O atoms = -10 total charge.
- 2 V atoms must total +10 → each V = +5
→ Vanadium (V) oxide
5. Ba₃(PO₄)₂
Step 1: Cation = Barium (Ba²⁺)
Step 2: Anion = PO₄³⁻ (polyatomic, do NOT change ending)
3 Ba²⁺ = +6
2 PO₄³⁻ = -6
→ Balanced, no Roman numeral needed
→ Barium phosphate
Explanation
Chemical compounds are named based on whether they are covalent or ionic. Covalent compounds are made of two nonmetals and use prefixes to show the number of atoms. For example, P₄O₁ becomes tetraphosphorus monoxide. The prefix “tetra-” shows there are four phosphorus atoms, and “mono-” is used (even though often omitted for the first element) to indicate one oxygen atom. Similarly, C₂N is dicarbon mononitride, and N₂Hg is dinitrogen monomercury—though rare, covalent compounds with metals like mercury are sometimes named this way for consistency.
Ionic compounds are composed of a metal and a nonmetal (or a polyatomic ion). Naming them involves saying the metal (cation) first, then the nonmetal (anion) with an “-ide” ending—unless the anion is a polyatomic ion, like phosphate. In V₂O₅, vanadium is a transition metal, so we must determine its charge. Oxygen is always -2; with 5 oxygen atoms, that’s -10. To balance this, the two vanadium atoms must total +10, so each is +5, making the name vanadium (V) oxide.
Ba₃(PO₄)₂ features barium (Ba²⁺), a Group 2 metal, and phosphate (PO₄³⁻). Three Ba²⁺ ions contribute +6 and two PO₄³⁻ ions contribute -6, making a neutral compound. Since barium is not a transition metal and its charge is fixed, no Roman numeral is needed, resulting in barium phosphate.
Understanding these naming conventions helps chemists communicate clearly about compounds’ compositions and properties.
