Question

A nitrogen nucleus ${}_7^{14}N$ absorbs a neutron and can transform into lithium nucleus ${}_3^{7}Li$ under suitable conditions, after emitting:
(i) $4$ protons and $3$ neutrons
(ii) $5$ protons and $1$ beta particle
(iii) $2$ alpha particles and $2$ gamma photons
(iv) $1$ alpha particle, $4$ protons and $2$ beta particles
(v) $4$ protons and $4$ neutrons.

• A. (i), (iii), (iv)
• B. (ii), (iii), (v)
• C. (iii), (iv, (v)
• D. (i), (ii), (iii)

Answer 1

The correct option is C (iii), (iv, (v)

$\begin{array}{c}\text{Given}-\text{*}{}^{14}N\text{transforms into}{}^7\text{Li after gaining}\\ \text{a neutron.}\\ \text{In the given transformation, we have -}\\ \text{* Change in atomic mass}=8\text{(decreases)}\\ \text{Choice(i):}4\text{protons and}3\text{neutrons.}\\ \text{* Change in atomic number}=4\text{(decreases)}\\ \text{* mass decreases by}=7\text{units.}\\ \text{* Atomic no. decreases by = 4units}\end{array}$

$\text{Choice(ii): 5 protons and}1\beta \text{particle.}$

$\text{* mass decreases by 5 units.}$

$\text{* Atomic number decreases by = 4 units.}$

$\text{Choice (iii):}2\alpha \text{particles,}2\gamma \text{particles}$

$\ast \text{mass decreases by}=8\text{units.}$

$\ast \text{Atomic number decreases by = 4 units.}$

$\text{Choice (iv):}1\alpha \text{particle, 4 protons,}2\beta \text{particles}$

$\ast \text{mass decreases by}=8\text{units.}$

$\text{* Atomic num decreases by = 4 wnits.}$

$\text{Choice (v): * 4protons and 4 neutrons}$

$\ast \text{mass decreases by}=8\text{units.}$

$\text{* Atomic num decreases by}=4\text{units.}$

$\text{only,(iii) (iv) (v) is applicable.}$

$\text{Hence, option (c) is correct.}$