Question

The 'Group displacement law' was given by: (a) Bacqueral (b) Rutherford (c) Madam Curie (d) Soddy and Fajan

Short answer

The 'Group displacement law' was given by (d) Soddy and Fajan.

Step-by-step solution

Identify the Concept

The 'Group displacement law' refers to the law in radioactivity that explains the change in the position of an element on the periodic table when it emits alpha or beta particles. Alpha emission causes an element to move back two places (a decrease by 2 in atomic number), while beta emission causes an element to move forward one place (an increase by 1 in atomic number).

Determine the Scientists

To find out who proposed the 'Group displacement law', look up the discovery in historical references or reliable scientific sources.

Recognize the Contributors

Friedrich Soddy and Kazimierz Fajans independently formulated the Group Displacement Law in 1911. They are credited with identifying how alpha and beta particle emissions affect the atomic number of elements.

Key concepts

Radioactivity

Radioactivity is a natural phenomenon that occurs when an unstable atomic nucleus loses energy by emitting radiation. This process can produce alpha, beta, or gamma rays, and it is an intrinsic property of certain isotopes, which are variants of elements with different numbers of neutrons.

The study of radioactivity has played a vital role in understanding atomic structure and the changes that occur within an atom. It has applications ranging from medical treatments to energy production. Easy to understand, think of radioactivity like a basketball deflating over time; the ball (nucleus) releases air (radiation) until it's stable.

Periodic Table

The periodic table is a tabular arrangement of chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. Elements are presented in rows, or periods, and columns, or groups.

It is a fundamental tool for students and chemists to predict the properties of elements and their compounds. Imagine the periodic table as a library, where each book (element) is organized by genre (chemical properties) and book number (atomic number) to help you find the information (element properties) you need efficiently.

Alpha Emission

Alpha emission is a type of radioactive decay where an alpha particle, which consists of two protons and two neutrons, is emitted from the nucleus of an unstable atom. This process decreases the atomic number by 2 and the mass number by 4, leading to the formation of a new element.

In simpler terms, it's like removing a pair of shoes (alpha particle) from a packed suitcase (nucleus) to make it lighter and more stable, while simultaneously changing the label on the suitcase (element identity).

Beta Emission

Beta emission involves the release of beta particles, which are high-energy, high-speed electrons or positrons, during radioactive decay. A neutron in an unstable nucleus is transformed into a proton and a beta particle, causing an increase in the atomic number by 1, but the mass number remains unchanged.

Consider beta emission as a kind of identity swap in a group of people (nucleus) where one person (neutron) changes their outfit (charge) and becomes another person (proton), adding to the group's diversity without affecting its overall size (mass number).

Historical Scientific Contributions

The scientific advancements in understanding radioactivity have been made possible by numerous historical contributions. Friedrich Soddy and Kazimierz Fajans' collective work on the Group Displacement Law in 1911 is one such example. They established how the identity of elements changes due to radioactive emissions, which contributed immeasurably to our comprehension of nuclear chemistry.

Like solving a complex puzzle, these historical scientists pieced together the behavior of elements, contributing foundational knowledge that continues to underpin many modern scientific and technological fields.