Question

If Au-185 emits an alpha particle, what is the nucleus formed?

Answer 1

Given:

Au 185 emits an alpha particle

Required: The nucleus formed after alpha particle emission from Au 185

Step-by-step explanation:

When an alpha particle is emitted from any nucleus, it losses its mass number by 4 and atomic number by 2.

Here, the alpha particle is emitted from the Au nucleus.

The mass number of Au is 185, so when an alpha particle is emitted, the newly formed nucleus will have the mass number

`\begin{gathered} M=185-4 \\ =181 \end{gathered}`

Also, the atomic number of Au is 79, so after alpha particle emission, its atomic number will be

`\begin{gathered} A=79-2 \\ =77 \end{gathered}`

Thus, the newly formed nucleus will have 181 mass number and 77 atomic number.

The nucleus with 181 mass number and 77 atomic number is Iridium.

Final Answer: Iridium nucleus is formed.