Chapter 25, Problem 63A

(a)

Interpretation Introduction

Interpretation:

Describe the contributions of Marie Curie in the study of radioactivity and nuclear chemistry.

Concept Interpretation:

Maria Sklodowska-Curie discovered radium and polonium, earning her the 1911 Nobel Prize in Chemistry.

Answer to Problem 63A

Through her experiments, Marie Curie discovered a number of radioactive elements and defined the process of radioactivity.

Explanation of Solution

The Curies discovered polonium and radium salts weighing about 0.1 gram from tonnes of uranium ore after carefully isolating various substances through successive chemical reactions and crystallizations of the products, which they then tested for their ability to ionize the air.

Marie succeeded in creating a pure specimen of radium after Pierre passed away in 1906 after being inadvertently hit by a horse-drawn cart. She was given access to radium institutes in Poland and France just before World War I to further study the scientific and medicinal applications of radioactivity. To aid with the care of injured French soldiers during the war, Curie organized a field network of transportable X-ray devices.

(b)

Interpretation Introduction

Interpretation:

Describe the contributions of Antoine Henri Becquerel in the study of radioactivity and nuclear chemistry.

Concept Interpretation:

He stumbled across the fact that uranium salts emit penetrating radiation that may be recorded on a photographic plate. Further research demonstrated that this radiation was novel and not X-ray radiation; he had found radioactivity, a novel phenomenon.

Answer to Problem 63A

Spontaneous radioactive decay of uranium salts was the natural radioactivity that Becquerel unintentionally discovered.

Explanation of Solution

After conducting research with uranium salts and exposing them to sunlight, Antoine Henri Becquerel unexpectedly discovered that uranium salts could also fog film and emit radioactive radiation without exposure to sunlight.

(c)

Interpretation Introduction

Interpretation:

Describe the contributions of James Chadwick in the study of radioactivity and nuclear chemistry.

Concept Interpretation:

In the field of nuclear science, Chadwick made a key discovery when he established the existence of neutrons, elementary particles devoid of any electrical charge.

Answer to Problem 63A

James Chadwick discovered neutrons as subatomic particles present in each atom.

Explanation of Solution

After Rutherford's discovery, James Chadwick found that every atom's nucleus contains subatomic particles called neutrons during an experiment involving the transformation of beryllium- $9$ . He used alpha particles to blast the beryllium- $9$ atom's nucleus in this experiment, which caused neutrons to be released.

(d)

Interpretation Introduction

Interpretation:

Describe the contributions of Ernest Rutherford in the study of radioactivity and nuclear chemistry.

Concept Interpretation:

He established the rules of radioactive decay, identified alpha particles as helium nuclei, and found alpha and beta rays.

Answer to Problem 63A

Rutherford made the first artificial transmutation and found artificial elements. This experiment resulted in the identification of the proton, a subatomic particle.

Explanation of Solution

In an experiment, Ernest Rutherford attacked nitrogen gas with alpha particles, resulting in the synthesis of the first synthetic element. An atom of one element is transformed into an atom of another element by radioactive decay or particle bombardment in a process known as transmutation.