Question

${}^{22}Ne$ nucleus, after absorbing energy, decays into two $\alpha -$ particles and an unknown nucleus. The unknown nucleus is

• A. nitrogen
• B. carbon
• C. boron
• D. oxygen

Answer 1

Answer: (B)

Atomic number of neon is 10.
By the emission of two $\alpha -$ particles, atomic number will be
reduced by 4. Therefore, atomic number of the unknown
element will be $Z=10-4=6$
Similarly, mass number of the unknown element will be
$A=22-2\times 4=14$
Unknown nucleus is carbon $(A=14,Z=6)$.