Binary Covalent Compounds Worksheet for chemistry practice.

Let’s solve this step by step.

We are given a worksheet with two parts:

Part 1: Write formulas for the following binary covalent compounds (names → formulas)
These are named using prefixes that tell us how many atoms of each element are in the molecule.

Prefixes:
- mono = 1 (usually omitted for first element)
- di = 2
- tri = 3
- tetra = 4
- penta = 5
- hexa = 6
- hepta = 7
- octa = 8
- nona = 9
- deca = 10

Rules:
- First element: use prefix if more than one atom.
- Second element: always use prefix + change ending to “-ide”.
- Never use “mono” on the first element.

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Let’s go through each name and write the formula.

1. Tetrasulfur nonoxide
→ S₄O₉
(“tetra” = 4 sulfur, “nona” = 9 oxygen)

2. Dinitrogen trioxide
→ N₂O₃
(di = 2 nitrogen, tri = 3 oxygen)

3. Iodine heptafluoride
→ IF₇
(no prefix on iodine = 1, hepta = 7 fluorine)

4. Silicon tetrabromide
→ SiBr₄
(silicon = 1, tetra = 4 bromine)

5. Phosphorus trifluoride
→ PF₃
(phosphorus = 1, tri = 3 fluorine)

6. Hexaboron silicide
→ B₆Si
(hexa = 6 boron, no prefix on silicon = 1 — but note: “silicide” means Si is second element, so it should be written as B₆Si? Wait — actually, in naming, the less electronegative element comes first. Boron and silicon — both metalloids, but conventionally we follow the order given. The name says “hexaboron silicide”, so boron first, then silicon. So yes: B₆Si. But wait — is that correct? Actually, “silicide” implies Si is the anion-like part, so it should be written last. Yes, B₆Si is fine. However, sometimes it's written as SiB₆? No — the name specifies “hexaboron” first, so B₆Si. Let me double-check standard practice. Actually, in covalent naming, the element farther left/lower in periodic table usually comes first. Boron is group 13, silicon group 14 — so boron should come first. So B₆Si is acceptable. But let’s confirm: common compound