Question

Match the following $$ \begin{array}{ll} \text { List-I } & \text { List-II } \\ \hline \text { (a) Highest density } & \text { (p) } \mathrm{Os} \\ \text { (b) Colourless salts } & \text { (q) } \mathrm{Cr} \\ \text { (c) Maximum magnetic } & \text { (r) } \mathrm{Zn} \\ \text { moment } & \\ \text { (d) Variable oxidation state } & \text { (s) } \mathrm{Mn} \end{array} $$

Short answer

(a) - (p), (b) - (r), (c) - (s), (d) - (q)

Step-by-step solution

Understand the matching criteria

First, we need to identify the unique property that can link entries in List-I to List-II. For example, the 'highest density' will likely match with an element known for having a high density.

Match Highest Density

Compare the metal density values to match the correct element. Osmium (Os) is known to have the highest density of any element, so match (a) with (p).

Identify Colourless Salts Producer

Colourless salts are often produced by elements whose compounds don't have strong color. Zinc (Zn) typically forms colourless or white salts, so match (b) with (r).

Determine Maximum Magnetic Moment

Elements with unpaired electrons in their d-orbitals typically exhibit strong magnetic moments. Manganese (Mn) can exhibit this property due to its electronic configuration, so match (c) with (s).

Find Variable Oxidation States

Identify the element that commonly exhibits various oxidation states. Chromium (Cr) is well-known for having multiple oxidation states, so match (d) with (q).

Key concepts

Element Properties

Element properties are key characteristics that help us understand the behavior and usage of the elements. Each element has unique traits such as atomic number, electronegativity, and electron configuration.
These properties determine the element's position in the periodic table and its chemical reactions.

• Atomic Number: Defines the number of protons in an atom's nucleus.
• Electron Configuration: Describes the distribution of electrons in an atom's orbitals.
• Density: A physical property representing mass per unit volume.
• Oxidation States: Shows the degree of oxidation of an element in compounds.

Understanding these properties aids in predicting how elements interact during chemical processes.

Density of Elements

The density of an element is a fundamental property that is defined as mass per unit volume. It is commonly expressed in grams per cubic centimeter (g/cm³).
Osmium (Os) notably holds the record for the highest density among all elements, with a value of about 22.59 g/cm³.

The high density of Osmium is due to its closely packed atomic structure and larger atomic mass. This property is crucial in applications that demand materials resistant to wear and abrasion, as it reflects high strength and endurance.
In the context of the periodic table, density generally increases as we move down a group due to the increase in atomic mass.

Magnetic Moment

The magnetic moment of an element is a measure of its magnetism, stemming from the presence of unpaired electrons within its atoms.
Magnetic moments occur because electrons have a property known as spin, and unpaired spins contribute to a net magnetic field. Manganese (Mn) is known to have a significant magnetic moment due to its unpaired electrons in the d-orbitals.

• If all electrons in an atom are paired, the magnetic moment is usually lower, resulting in a diamagnetic nature.
• If there are unpaired electrons, the element can exhibit paramagnetic or ferromagnetic properties, depending on the alignment of the spins.

Thus, understanding the magnetic moment is vital to predicting how materials will respond to magnetic fields.

Oxidation States

Oxidation states, also called oxidation numbers, refer to the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic.
They describe the degree of oxidation or reduction of an element in a chemical compound.
Chromium (Cr) is particularly notable for its varied oxidation states, commonly found as +2, +3, and +6 in compounds. This versatility allows chromium compounds to be used in various applications, including pigments and tanning leather.

• A positive oxidation state indicates a loss of electrons (oxidation).
• A negative oxidation state indicates a gain of electrons (reduction).

Understanding oxidation states aids in balancing equations and predicting the types of reactions an element can undergo.