P Block Elements

Step 1: Understanding electronic configuration.
The given configuration corresponds to an element that fills orbitals in the 5th period. It is found in the 5th period and has electrons in both the 5s and 4d orbitals, indicating that it belongs to a group of transition metals or post-transition elements. Step 2: Analyzing the options.
(A) Oxygen: Oxygen has an atomic number of 8, and its configuration is , so it doesn't match.
(B) Hydrogen: Hydrogen has an atomic number of 1, and its configuration is , which is far from the given configuration.
(C) Nitrogen: Nitrogen has an atomic number of 7, but the configuration provided here is likely for an element like Gallium, which is part of the p-block.
(D) Fluorine: Fluorine has an atomic number of 9, and its configuration is .
Step 3: Conclusion.
The correct answer is (C) because the element corresponding to this configuration is Nitrogen.

Step 1: Identifying laughing gas.
Laughing gas is a common name for nitrous oxide (N₂O), a colorless gas with a slightly sweet odor. It is used in medicine as a sedative and anesthetic. Step 2: Analysis of options.
(A) Nitric oxide: Nitric oxide (NO) is not called laughing gas. It is a gas involved in various biological processes but does not have the same properties as nitrous oxide.
(B) Nitrous oxide: Correct — Nitrous oxide (N₂O) is commonly known as laughing gas, used for its anesthetic effects.
(C) Dinitrogen trioxide: Dinitrogen trioxide (N₂O₃) is not known as laughing gas and is a different nitrogen oxide.
(D) Dinitrogen pentoxide: Dinitrogen pentoxide (N₂O₅) is another nitrogen oxide, but it is not referred to as laughing gas.
Step 3: Conclusion.
The correct answer is (B) because nitrous oxide is commonly known as laughing gas.

Step 1: Understanding the formula of Orthophosphoric acid.
Orthophosphoric acid, also known as phosphoric acid, is a mineral acid with the chemical formula . It contains three hydrogen atoms, one phosphorus atom, and four oxygen atoms. Step 2: Analysis of options.
(A) : This is the formula of phosphorous acid, not orthophosphoric acid.
(B) : Correct — This is the molecular formula of orthophosphoric acid.
(C) : This formula represents metaphosphoric acid, not orthophosphoric acid.
(D) : This is the formula for pyrophosphoric acid, not orthophosphoric acid.
Step 3: Conclusion.
The correct answer is (B) because is the molecular formula of orthophosphoric acid.

Step 1: Understanding XeF₄ structure.
Xenon tetrafluoride (XeF₄) has a square planar structure. This is because of the central xenon atom surrounded by four fluorine atoms with lone pairs of electrons on xenon. The lone pairs occupy the axial positions, resulting in a square planar geometry for the bonding pairs. Step 2: Conclusion.
The correct answer is (C) because XeF₄ adopts a square planar geometry.

Step 1: Understanding halogen oxidation states.
Halogens typically exhibit negative oxidation states (-1) in most compounds, but they can also exhibit positive oxidation states. Fluorine, however, is highly electronegative and does not form positive oxidation states. Step 2: Analysis of options.
(A) I: Iodine can form positive oxidation states, such as +1, +3, +5, and +7.
(B) Br: Bromine can form positive oxidation states, such as +1, +3, +5, and +7.
(C) Cl: Chlorine can form positive oxidation states, such as +1, +3, +5, and +7.
(D) F: Fluorine always has an oxidation state of -1 due to its high electronegativity.
Step 3: Conclusion.
The correct answer is (D) because fluorine does not exhibit a positive oxidation state.

Step 1: Analyze the structure and stability of PCl and NCl .
- PCl (phosphorus pentachloride) is a stable compound because phosphorus can expand its valence shell to accommodate five chlorine atoms. Phosphorus has a relatively large atomic size and can form stable bonds with chlorine atoms. The molecule adopts a trigonal bipyramidal structure, which is stable. - NCl (nitrogen trichloride), however, is not as stable. Nitrogen is smaller and does not have the ability to expand its valence shell in the same way phosphorus does. Therefore, nitrogen can only form three bonds, making NCl less stable. Additionally, NCl is highly reactive and unstable, especially when exposed to heat or light, making it difficult to isolate.
Step 2: Conclusion.
- PCl is stable due to the ability of phosphorus to form five bonds, while NCl is unstable because nitrogen cannot accommodate more than three bonds.
Final Answer: PCl is stable because phosphorus can expand its valence shell to form five bonds, whereas NCl is unstable because nitrogen cannot expand its valence shell beyond three bonds.
Final Answer:

Step 1: Understand the structure of nitrogen.
Nitrogen (N ) is a diatomic molecule with a triple bond between the two nitrogen atoms. The triple bond consists of one sigma bond and two pi bonds, making it very strong and stable.
Step 2: High bond dissociation energy.
The high bond dissociation energy required to break the N≡N triple bond makes nitrogen molecules less reactive. This means that a significant amount of energy is needed to break the bond and initiate a reaction.
Step 3: Electron pairing and stability.
Nitrogen atoms in the N molecule have a stable electron configuration with a full outer shell, and the molecule has no available lone pairs or empty orbitals to react easily with other molecules. This lack of reactivity is due to the inertness of the nitrogen molecule.
Step 4: Conclusion.
Nitrogen molecules are less reactive due to the strength of the triple bond and the stability of the molecule.
Final Answer: Nitrogen molecules are less reactive because of the strong triple bond between nitrogen atoms and the stability of the molecule.
Final Answer:

Step 1: Understand the concept of oxidizing agent.
An oxidizing agent is a substance that gains electrons in a chemical reaction, causing the oxidation of another substance. It essentially facilitates the oxidation process by accepting electrons.
Step 2: Understand why is a strong oxidizing agent.
Ozone ( ) is a strong oxidizing agent because of its molecular structure. The oxygen-oxygen bonds in ozone are weak, making it easy for the molecule to decompose and release oxygen atoms. These released oxygen atoms can react with other molecules, oxidizing them.
Step 3: Reaction example.
When ozone reacts with an electron donor (such as a metal or organic compound), it gains electrons and forms , thereby oxidizing the other substance. For example: The released atomic oxygen ( ) is highly reactive and can readily oxidize other substances.
Final Answer: Ozone behaves as a strong oxidizing agent due to its ability to release reactive oxygen atoms, which readily oxidize other substances.
Final Answer: