All questions of p-Block Elements for JEE Exam

The element M in the complex ion MF6^3-  has a coordination number of six. Since B has only s- and p-orbitals and no d – orbitals, therefore, at the maximum it can show a coordination number of 4. Thus, B cannot form complex of the type MF6^3-, i.e., option (a) is correct.

Explanation:

Fluorine differs from the rest of the halogens in some of its properties due to the lack of d-orbitals. The explanation for this can be understood by considering the electronic configuration and the atomic structure of fluorine.

Electronic Configuration:
Fluorine has an atomic number of 9, and its electronic configuration is 1s2 2s2 2p5. It has a completely filled 2s orbital and an incomplete 2p orbital with one electron in each of the three available 2p orbitals.

Atomic Structure:
The atomic structure of fluorine consists of a nucleus at the center, which contains 9 protons and 9 neutrons. Surrounding the nucleus are two energy levels or shells, with the first shell containing 2 electrons and the second shell containing 7 electrons.

Lack of d-orbitals:
Fluorine does not have any d-orbitals in its valence shell. The valence shell of an atom is the outermost shell that participates in chemical bonding. In the case of fluorine, the valence shell is the second shell, which contains 7 electrons in the 2s and 2p orbitals. Since the second shell does not have any d-orbitals, fluorine cannot accommodate any d-electrons.

Consequences:
The lack of d-orbitals in fluorine has several consequences that distinguish it from the rest of the halogens:

1. Size: Fluorine is the smallest halogen atom due to its smaller atomic radius. This is because the lack of d-orbitals results in a more compact electron cloud around the nucleus.

2. Electronegativity: Fluorine has the highest electronegativity among the halogens. This is because the lack of d-orbitals allows the 2p orbitals to be closer to the nucleus, leading to greater attraction for bonding electrons.

3. Bond Dissociation Energy: Fluorine has a higher bond dissociation energy compared to the other halogens. Bond dissociation energy is the energy required to break a bond in a molecule. The lack of d-orbitals in fluorine results in stronger bonds, making it more difficult to break them.

In summary, the lack of d-orbitals in fluorine's valence shell leads to its smaller size, higher electronegativity, and higher bond dissociation energy, which distinguish it from the rest of the halogens.

Structure of White Phosphorus

White phosphorus (P4) is a molecular form of phosphorus that exists as a tetrahedral structure. Each phosphorus atom in the white phosphorus molecule is bonded to three other phosphorus atoms, resulting in a tetrahedral arrangement.

Explanation

Phosphorus is a chemical element with the atomic number 15 and is located in Group 15 of the periodic table. It exists in several different forms, including white, red, and black phosphorus.

White phosphorus is the most common and well-known form of phosphorus. It is a waxy, translucent solid that appears white or slightly yellow. The structure of white phosphorus consists of P4 molecules, where four phosphorus atoms are covalently bonded together in a tetrahedral arrangement.

Tetrahedral Structure

The tetrahedral structure is characterized by the arrangement of four atoms or groups of atoms around a central atom, forming a pyramid shape. In white phosphorus, each phosphorus atom is bonded to three other phosphorus atoms, resulting in a tetrahedral arrangement.

Key Points:
- White phosphorus has a tetrahedral structure.
- It consists of P4 molecules.
- Each phosphorus atom is bonded to three other phosphorus atoms.
- The tetrahedral arrangement gives white phosphorus its unique properties and reactivity.

Properties and Reactivity

White phosphorus is highly reactive and flammable. It ignites spontaneously in air at room temperature, producing a bright flame and releasing toxic fumes. This reactivity is due to the presence of weak P-P bonds in the tetrahedral structure, which can easily break and react with oxygen in the air.

White phosphorus is also known for its high toxicity and ability to form poisonous compounds. It is used in various applications, including military ammunition, pesticide production, and the synthesis of other phosphorus compounds.

Conclusion

In summary, the structure of white phosphorus is tetrahedral, with each phosphorus atom bonded to three other phosphorus atoms. The tetrahedral arrangement gives white phosphorus its unique properties and reactivity, making it a useful but highly dangerous substance.