# How many α and β-particles are emitted in the transmutation X90232X2902232Th⟶X82208X2822208Pb? - Chemistry

How many α and β-particles are emitted in the transmutation $\ce{^232_90Th -> ^208_82Pb}$?

#### Solution

$\ce{^232_90Th -> ^208_82Pb}$

The emission of one α-particle decreases the mass number by 4 whereas the emission of β-particles has no effect on the mass number.

Net decrease in mass number = 232 - 208 = 24.

This decrease is only due to α-particles. Hence, number of α-particles emitted = 24/4 = 6

Now, the emission of one α-particle decreases the atomic number by 2 and one β-particle emission increases it by 1.

The net decrease in atomic number = 90 - 82 = 8

The emission of 6 α-particles causes a decrease in atomic number by 12. However, the actual decrease is only 8.

Thus, the atomic number increases by 4. This increase is due to the emission of 4 β-particles.

Thus, 6 α and 4 β-particles are emitted.

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#### APPEARS IN

Balbharati Chemistry 11th Standard Maharashtra State Board
Chapter 13 Nuclear Chemistry and Radioactivity
Exercises | Q 3. (P) | Page 203