A radioactive nucleus ' D ' is decaying in the following way: D 92 235 → α decay D 1 → β - decay D 2 → α decay D 3 → γ decay D 4 Determine the atomic number and mass number of D 4 .

As we know,mass and charge of α = 4 a n d + 2 β = 0 a n d - 1 γ = 0 a n d 0 So, m 180 176 176 172 172 e 72 70 71 69 69 The atomic number and mass number of D 4 is 172 a n d 69 ...

If 2 α particles and 3 β particles emit in series decay of a radioactive nucleus Ra 88 228 and nucleus Y is obtained at last then find atomic number and mass number of Y .

In first, the radioactive Ra 228 88 nucleus. 2 α particles and 3 β particles emit in series decay of a radioactive nucleus. Then in 2 α decay, Ra 228 88 → - 2 α Z 220 84 In 3 β decay, Z 220 84 → - 3 β Y 220 87 Atomic number of Y = 87 Atomic number of A = 220 Ra 228 88 → Z 220 84 + 2 He 4 2 α particle Z 220 84 → Y 220 87 + 3 β ° - 1 β particle Hence, it is the required answer.

α - decay is a process in which the nucleus of a radioactive element emits an alpha particle. α - particle is a doubly ionised helium atom H 2 4 e + + so by emitting an alpha particle the mass number of the daughter nucleus is reduced by 4 and the atomic number is reduced by 2 . A general alpha decay process can be represented by the following equation.: X Z A → Y Z - 2 A - 4 + He 2 4 This spontaneous emission of the α particle is possible only when the total mass of decay products is less than that of the initial nucleus.

In the reaction X Z A → Y Z - 2 A - 4 + H 2 4 e + Q of the nucleus X at rest. Taking the ratio of the mass of the α - particle M u and the mass of Y nucleus as M U M Y = 4 A - 4 show that the Q value of the reaction is given by Q = K α A A - 4 where K α is the kinetic energy of the α -particle.

Given the reaction X Z A → Y Z - 2 A - 4 + He 2 4 + Q To prove that Q = K α A A - 4 The kinetic energy of α particle is given by K α = mass no . after decay mass no . before decay × Q = A - 4 A Q The Q value is given by Q = M α - M y M y × K α = 4 - A - 4 A - 4 × Q = A A - 4 A - 4 A Q = Q hence proved.

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Let nuclide $A$ be $α -$ emitter and nuclide $B$ be $β -$ emitter. Both $A$ and $B$ contain large number of nuclei. Choose the correct statement:

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Important Questions on Atoms and Nuclei

MEDIUM

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

Give one example each of Alpha, Beta and Gamma decay.

MEDIUM

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

A radioactive nucleus

\begin{matrix} A \\ Z \end{matrix} X

undergoes spontaneous decay in the sequence

\begin{matrix} A \\ Z \end{matrix} X \to \begin{matrix} (Z - 1) \end{matrix} B \to \begin{matrix} (Z - 3) \end{matrix} C \to \begin{matrix} (Z - 2) \end{matrix} D

, where

Z

is the atomic number of element

X

. The possible decay particles in the sequence are:

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

The ionisation power is maximum for:

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

A radioactive nucleus $' D'$ is decaying in the following way:

${}_{92}^{235}D \overset{α decay}{\to} D_{1} \overset{β^{-} decay}{\to} D_{2} \overset{α decay}{\to} D_{3} \overset{γ decay}{\to} D_{4}$

Determine the atomic number and mass number of $D_{4}$ .

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

A nucleus of uranium decays at rest into nuclei of thorium and helium. Then:

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

2 α

particles and

3 β

particles emit in series decay of a radioactive nucleus

{}_{88}{Ra}^{228}

and nucleus

Y

is obtained at last then find atomic number and mass number of

Y

HARD

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

The nucleus ${}_{92}^{235}Y$ , initially at rest, decays into ${}_{90}^{231}X$ by emitting an $α -$ particle.

${}_{92}^{235}Y \to {}_{90}^{231}X + {}_{2}^{4}{He} +$ energy

The binding energy per nucleon of the parent nucleus, the daughter nucleus and $α -$ particles are $7.8 Mev, 7.835 Mev$ and $7.07 Mev$ , respectively. Assuming the daughter nucleus to be formed in the excited state and neglecting its share in the energy of the reaction, find the speed of the emitted $α -$ particle. (Mass of $α -$ particle $= 6.68 \times 10^{- 27} kg$ )

MEDIUM

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

Write the nuclear reaction equation for the alpha decay of ${}_{92}^{238}U$ .

HARD

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

In a radioactive decay chain,

_{90}^{232} Th

nucleus decays to

_{82}^{212} Pb

nucleus. Let

N_{α} and N_{β}

be the number of

α and β^{-}

particles, respectively, emitted in this decay process. Which of the following statements is (are) true?

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

In radioactive reaction,

${}_{Z}^{A}X \to {}_{Z + 1}^{A}X_{1} \to {}_{Z + 2}^{A}X_{2} \to {}_{Z}^{A - 4}X_{3} \to {}_{Z + 1}^{A - 4}X_{4}$

Radioactive radiation are emitted in the sequence:

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

{}_{10}^{22}{Ne}

nucleus decays into two

α

-particles and an unknown nucleus. The unknown nucleus is

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

The end product of decay of

_{90} {Th}^{232}

_{82} {Pb}^{208}

. The number of

α

and

β

particles emitted are respectively

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

Spontaneous and continuous disintegration of a nucleus of a heavy element with the emission of certain types of radiation is known as radioactivity.

The radioactive isotope $' D'$ decays according to the sequence $D \overset{β^{-}}{\to} D_{1} \overset{α}{\to} D_{2}$

If the mass number and atomic number of $D_{2}$ are $172$ and $71$ respectively, what are the: $(i)$ Mass number, $(ii)$ Atomic number of $D$ .

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

$A \overset{α}{\to} A_{1} \overset{β}{\to} A_{2} \overset{α}{\to} A_{3}$

The mass number and atomic number of $A$ are $180$ and $72$ respectively. What are these numbers for $A_{3}$ ?

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Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

Explain Alpha Decay.

HARD

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

When plutonium ${}_{94}^{242}P u$ undergoes $α$ decay an isotope of uranium is obtained. Write the equation for this nuclear reaction. A radioactive nucleus undergoes a series of decays according to the following reactions. Find the mass number and atomic number of C.

${}_{27}^{60}A \overset{β^{-}}{\to B} \overset{γ^{-}}{\to C}$

MEDIUM

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

In the reaction

{}_{Z}^{A}X \to {}_{Z - 2}^{A - 4}Y + {}_{2}^{4}H e + Q

of the nucleus

X

at rest. Taking the ratio of the mass of the

α

- particle

M_{u}

and the mass of

Y

nucleus as

\frac{M_{U}}{M_{Y}} = \frac{4}{A - 4}

show that the

Q

value of the reaction is given by

Q = K_{α} (\frac{A}{A - 4})

where

K_{α}

is the kinetic energy of the

α

-particle.

MEDIUM

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

{}_{92}{U^{238}}

changes to

{}_{85}{At}^{210}

by a series of

α

- and

β

-decays, the number of

α

- and

β

-decays undergone, respectively, is

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

The number of

α

-particles emitted during the radioactive decay chain from

{}_{88}^{226}{Ra}

and ending at

{}_{82}^{206}{Pb}

EASY

Physics>Modern Physics>Atoms and Nuclei>α, β and γ Radiations

A decay chain of the nucleus

{}_{92}^{238}U

involves eight

α

-decays and six

β

-decays. The final nucleus at the end of the process will be

Let nuclide A be α-emitter and nuclide B be β-emitter. Both A and B contain large number of nuclei. Choose the correct statement:

Important Questions on Atoms and Nuclei

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Let nuclide $A$ be $α -$ emitter and nuclide $B$ be $β -$ emitter. Both $A$ and $B$ contain large number of nuclei. Choose the correct statement: