Chapter 18, Problem 1RQ

(a)

Interpretation Introduction

Interpretation:

Association of Antoine Henri Becquerel with the early history of radioactivity has to be determined.

Concept Introduction:

Radioactivity is a nuclear process. It can be defined as the spontaneous disintegration of a nucleus which is done by the emission of radiation. The elements which show this property is said to be radioactive elements.

Explanation of Solution

Antoine Henri Becquerel (1852-1908) found radioactivity by experiments with uranium and many other substances. He showed a relationship between X rays and the phosphorescence of uranium salts. He performed an experiment in that photographic plate is wrapped with a piece of black paper and then he placed a sample of uranium salt in it and kept it to be exposed in sunlight. As a result, the photographic plate was developed. Then, he repeated that same experiment in the absence of light, and he found that the photographic plate was developed. Thus it was found that uranium salts emitted rays that developed the photographic plate in the absence of sunlight. In this way, the concept of radioactivity was discovered.

(b)

Interpretation Introduction

Interpretation:

Associations of Marie Sklodowska Curie and Pierre Curie with the early history of radioactivity have to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

Marie Sklodowska Curie (1867-1934) and her husband Pierre Curie (1859-1906) performed research in the field of radioactivity. They were renowned chemists. They discovered two new radioactive elements named radium and polonium. They performed their research work on radium. They also performed further investigations on the properties and atomic mass of radium.

(c)

Interpretation Introduction

Interpretation:

Association of Wilhelm Conrad Roentgen with the early history of radioactivity has to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

Wilhelm Conrad Roentgen (1845-1923) was the first person who discovered X rays and studied them systematically. He observed electromagnetic radiations were emitted from the discharge tube and penetrated the box and the salt started to glow. He also observed that X rays could pass through other substances also and it could affect photographic plates which led to X-ray photography.

(d)

Interpretation Introduction

Interpretation:

Association of Ernest Rutherford with the early history of radioactivity has to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

Ernest Rutherford (1871-1937) found that radioactive rays emitted by uranium from his experiment. He was known as the father of nuclear physics. In the year 1899, he performed experiments and found the absorption of radioactivity He discovered alpha and beta particles. The alpha particles were named by him as $\text{He}$ nuclei.

(e)

Interpretation Introduction

Interpretation:

Associations of Otto Hahn and Fritz Strassman and their associations with the early history of radioactivity have to be determined.

Concept Introduction:

Refer to part (a).

Explanation of Solution

Otto Hahn (1879-1968) was a famous scientist in the field of radioactivity. He worked with Fritz Strassman and they discovered the fission of uranium when it was bombarded by a neutron.