IB Chemistry Test Prep

Explanation
Van der Waals forces are the weakest type of bonding among the options given. These forces occur between atoms or molecules due to temporary fluctuations in electron distribution, causing temporary dipoles. These temporary dipoles induce dipoles in neighboring atoms or molecules, leading to weak attractive forces. In comparison, ionic bonding involves the transfer of electrons between atoms, covalent bonding involves the sharing of electrons, and hydrogen bonding is a strong type of dipole-dipole interaction.

Explanation
Allotropy refers to the property of certain elements to exist in multiple forms or allotropes. Tin, sulphur, and phosphorus all exhibit allotropy, meaning they can exist in different forms with different physical and chemical properties. However, hydrogen does not exhibit allotropy as it exists as a diatomic molecule (H2) in its most stable form.

Explanation
An atom is the smallest and indivisible unit of an element. It is the basic building block of matter and consists of a nucleus, which contains protons and neutrons, surrounded by electrons. Atoms combine to form molecules, but they cannot be further broken down into smaller particles without losing their chemical properties. Isotopes are different forms of the same element with varying numbers of neutrons, while allotropes are different forms of an element that exist in the same physical state. Therefore, the correct answer is atom.

Explanation
The combining power of an element refers to its ability to combine with other elements to form compounds. Oxygen has a combining power of -2 because it can gain two electrons to achieve a stable electron configuration. This allows oxygen to form compounds by accepting electrons from other elements, resulting in a negative charge of -2.

Explanation
Michael Faraday developed the theory of electrolysis. He made significant contributions to the field of electromagnetism and is known for his experiments on the relationship between electricity and chemical reactions. Faraday's work on electrolysis laid the foundation for our understanding of the process, including the concept of ions and their movement in an electric field. His discoveries revolutionized the field of chemistry and had a profound impact on various industries, such as electroplating and the production of metals.

Explanation
Sodium is not electronegative. Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. Sodium has a relatively low electronegativity value compared to other elements. In contrast, iodine is highly electronegative, meaning it has a strong ability to attract electrons.

Explanation
Casseterite is the correct answer because it is a mineral form of tin dioxide. It is the main ore of tin and is commonly used as a source of tin in various industries. Protium and deuterium are isotopes of hydrogen, and a salt bridge is a laboratory apparatus used in electrochemistry. Therefore, none of these options match 'tin' except for casseterite.

Explanation
Oxidation is the correct answer because it is a chemical reaction in which a substance loses electrons. This process leads to an increase in the oxidation state of the substance, resulting in the loss of electrons.

Explanation
Dmitri Mendeleev is the correct answer for the author of the periodic law of elements. Mendeleev was a Russian chemist who is credited with developing the periodic table of elements. He organized the elements based on their atomic mass and noticed that there was a periodic pattern in their properties. This led to the formulation of the periodic law, which states that the properties of elements are periodic functions of their atomic numbers. Mendeleev's work laid the foundation for our modern understanding of the organization and classification of elements.

Explanation
Neutralization reactions occur when an acid and a base react to form a salt and water. The acid donates a proton (H+) to the base, forming water, while the remaining ions from the acid and base combine to form a salt. This reaction results in the release of salt and water only, making neutralization the correct answer.