To find the atomicity of a homonuclear molecule, you divide its molecular weight by its atomic weight.
Understanding Atomicity
Atomicity refers to the total number of atoms present in a single molecule of a substance. It's a key concept in chemistry that helps us understand the structure and properties of molecules. Understanding how to calculate atomicity, particularly for homonuclear molecules, is fundamental in chemistry.
Calculating Atomicity of Homonuclear Molecules
As mentioned in the reference, the atomicity of a homonuclear molecule (a molecule made up of the same type of atoms) can be easily calculated. Here’s the process:
- Identify the molecular weight: Find the total weight of the molecule. This is usually found in the periodic table or chemical databases.
- Identify the atomic weight: Find the atomic weight of the individual atoms that make up the molecule.
- Divide: Divide the molecular weight by the atomic weight.
- Round: The result is often a whole number or very close to it. Round to the nearest whole number, which will give you the atomicity.
Example: Oxygen (O₂)
Let’s use the example provided in the reference for oxygen:
| Property | Value |
|---|---|
| Molecular Weight (O₂) | 31.999 |
| Atomic Weight (O) | 15.879 |
| Calculation | 31.999 / 15.879 ≈ 2 |
| Atomicity | 2 |
As shown above, by dividing the molecular weight of oxygen (31.999) by the atomic weight of a single oxygen atom (15.879), we get approximately 2. This indicates that each molecule of oxygen gas (O₂) is made of two oxygen atoms.
Practical Insights
- Homonuclear Molecules Only: This method works specifically for homonuclear molecules. For heteronuclear molecules (molecules with different types of atoms), you need to know the chemical formula to determine atomicity.
- Rounding: You should always round the result to the nearest whole number, which is an approximation.
Summary
In short, calculating the atomicity of a homonuclear molecule involves simply dividing the molecular weight by the atomic weight of its constituent atoms. The number you get, typically rounded to the nearest whole number, represents the number of atoms in that molecule.
