Question

Which of the following statements is wrong? (1) Elements of Group 2 are good conductors of electricity and heat. (2) Compounds of Group 2 elements are diamagnetic in nature. (3) The salts of Group 2 elements are more heavily hydrated than those of elements of group 1 . (4) Element of Group 2 are more electropositive than Group 1 elements.

Short answer

Statement 4 is wrong.

Step-by-step solution

- Analyze Statement 1

Group 2 elements, also known as alkaline earth metals, are indeed good conductors of electricity and heat. Examples include magnesium and calcium, which are metallic in nature and possess free-electron characteristics. Therefore, Statement 1 is correct.

- Analyze Statement 2

Compounds of Group 2 elements are generally diamagnetic because they have paired electrons. For instance, calcium carbonate (CaCO₃) and magnesium oxide (MgO) are diamagnetic. Therefore, Statement 2 is correct.

- Analyze Statement 3

The salts of Group 2 elements, such as calcium chloride (CaCl₂), are indeed more heavily hydrated compared to their Group 1 counterparts, such as sodium chloride (NaCl). This is because Group 2 cations have a higher charge density, leading to a stronger attraction to water molecules. Therefore, Statement 3 is correct.

- Analyze Statement 4

Group 2 elements are not more electropositive than Group 1 elements. Electronegativity decreases down a group and increases across a period; hence, Group 1 elements (alkali metals) are more electropositive than Group 2 elements. Therefore, Statement 4 is the incorrect one.

Key concepts

Electrical Conductivity

Group 2 elements, also known as alkaline earth metals, are excellent conductors of electricity and heat. This is due to their metallic nature, which means they have free electrons that can move easily through the metallic lattice. Examples of Group 2 elements include magnesium (Mg) and calcium (Ca). These metals have a high density of free electrons, which facilitates the conduction of electricity and heat. Thus, the metals can easily transfer energy through their electron cloud, thereby making them good conductors. Multiple electrons in the outer shell play a critical role in the conduction properties, ensuring that these metals maintain their conductive abilities.

Diamagnetic Properties

Diamagnetic materials are those that create an opposing magnetic field when subjected to an external magnetic field. Compounds of Group 2 elements typically exhibit diamagnetic properties because they generally have paired electrons. When all electrons are paired, their magnetic moments cancel out, resulting in no net magnetic moment. Examples include calcium carbonate (CaCO₃) and magnesium oxide (MgO), both of which have their electrons paired. Thus, they don't exhibit attraction to magnetic fields, classifying them as diamagnetic substances. This characteristic helps in distinguishing these compounds from paramagnetic and ferromagnetic materials, which have unpaired electrons and exhibit stronger magnetic properties.

Hydration of Salts

Hydration of salts refers to the process by which water molecules surround and interact with ions in a salt. Group 2 salts are more heavily hydrated compared to Group 1 salts. This is because Group 2 elements form cations (positively charged ions) with a +2 charge, which creates a higher charge density. This high charge density attracts water molecules more strongly than the +1 charged cations formed by Group 1 elements. For instance, calcium chloride (CaCl₂) attracts more water molecules around it compared to sodium chloride (NaCl). The strong electrostatic attraction between the cations and water molecules is what leads to the increased hydration observed in Group 2 salts.

Electropositivity

Electropositivity refers to the ability of an element to donate electrons and form positive ions. Group 2 elements are less electropositive compared to Group 1 elements. This is primarily due to their position in the periodic table. Group 1 elements are alkali metals and have only one electron in their outermost shell. This makes it easier for them to lose that electron and form a positive ion. On the other hand, Group 2 elements have two electrons in their outermost shell. Losing both of these electrons requires more energy compared to losing just one. Thus, elements like sodium (Na) and potassium (K) from Group 1 are more electropositive than magnesium (Mg) and calcium (Ca) from Group 2. In summary, the ease of losing electrons decreases from Group 1 to Group 2, making Group 1 elements more electropositive.