How To Name Covalent Molecular Compounds - The Easy Way!

Summary

This video explains how to name covalent (molecular) compounds, emphasizing the differences between molecular and ionic compounds. The instructor highlights that ionic compounds consist of metals and non-metals, whereas molecular compounds typically involve only non-metals. The video covers the essential prefixes for naming molecular compounds based on the number of atoms involved, such as 'mono' for one, 'di' for two, and so forth, up to 'deca' for ten. Using examples like CO, NO, and PCl3, the instructor guides viewers on properly applying these prefixes and understanding the 'ide' suffix rule for the more electronegative elements.

Takeaways

• 🔍 Understanding the distinction between molecular and ionic compounds is essential because the naming rules differ for each.
• 🧪 Molecular compounds typically consist of two non-metals, while ionic compounds often contain a metal and a non-metal.
• ⚖️ Prefixes like mono, di, tri, and others are used for naming molecular compounds but not for ionic compounds.
• 📏 The prefix 'mono' is not used for the first element in a molecular compound, even if it has a subscript of one.
• 🌍 The suffix '-ide' is added to the second element in molecular compounds.
• 🔢 Knowing the numerical prefixes is crucial: mono (1), di (2), tri (3), tetra (4), penta (5), hexa (6), hepta (7), octa (8), nona (9), and deca (10).
• 💡 Example: CO is named carbon monoxide, while CO₂ is carbon dioxide, demonstrating the use of these prefixes.
• 🔄 In molecular compounds, the more electronegative element is given the '-ide' suffix.
• 📚 Practice examples were provided to solidify understanding, including compounds like NO, N₂O₃, PCl₃, and PCl₅.
• 🔬 The video concluded with more complex examples like SiF₄, SF₆, IF₇, and P₄O₁₀, illustrating the application of these rules.

Q & A

What is the main difference between naming ionic and molecular compounds?

Ionic compounds do not use prefixes like 'mono,' 'di,' or 'tri,' while molecular compounds do use these prefixes to indicate the number of atoms in each element.

How can you easily identify if a compound is ionic or molecular?

An ionic compound typically contains a metal and a non-metal, while a molecular compound consists of two non-metals.

What is an example of an ionic compound and a molecular compound?

MgCl2 (magnesium chloride) is an ionic compound, while SCl2 (sulfur dichloride) is a molecular compound.

Why are prefixes like 'mono' or 'di' not used in ionic compounds?

Ionic compounds involve charges between ions, and the ratio of ions determines the compound's structure, so prefixes are unnecessary.

What prefixes are used for molecular compounds to represent numbers 1 to 5?

1 is 'mono,' 2 is 'di,' 3 is 'tri,' 4 is 'tetra,' and 5 is 'penta.'

How would you name CO and CO2 as molecular compounds?

CO is called carbon monoxide, and CO2 is called carbon dioxide. Note that 'mono' is used only for the second element, not the first.

How would you name a compound with two nitrogen atoms and five oxygen atoms?

The compound would be called dinitrogen pentoxide, where 'di' represents two nitrogen atoms and 'penta' represents five oxygen atoms.

What is the general rule for the ending of the second element in molecular compounds?

The second element typically ends in 'ide,' such as in 'monoxide' or 'pentoxide.'

How do electronegativity differences affect the naming of molecular compounds?

The more electronegative element is written second and ends with 'ide,' as seen in compounds like oxygen difluoride (OF2) where fluorine is more electronegative than oxygen.

Why is the 'a' sometimes omitted in names like 'decaoxide'?

When two vowels are next to each other, such as in 'decaoxide,' the 'a' is often dropped for easier pronunciation, resulting in 'decoxide.'