The thorium series starts with ^232_90Th and ends with stable ^208_82Pb. Which statements are correct?

Six alpha particles are emitted in the overall change.

The final nuclide has 126 neutrons.

The net decrease in the neutron number is 16.

Six alpha particles are emitted in the overall change.

Six beta^- particles are emitted in the overall change.

The final nuclide has 126 neutrons.

The net decrease in the neutron number is 16.

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3as191

The thorium series starts with $X_{90}^{232} X_{290}^{2232} Th$ and ends with stable $X_{82}^{208} X_{282}^{2208} Pb$ . Which statements are correct?

α

count

= (232 - 208) /4 = 6

(A true). These lower

Z

by 12 but the net fall is

90 - 82 = 8

, so

β^{-}

count

= 12 - 8 = 4

(B false). Neutrons in Pb-208

= 208 - 82 = 126

(C true). Neutrons in Th-232

= 232 - 90 = 142

, so the decrease is

142 - 126 = 16

(D true).