D Block Elements

Step 1: Electron Configuration of Mn
The electron configuration of Mn (atomic number 25) is [Ar] 3d⁵ 4s².
Step 2: Oxidation State and Electron Loss
In the oxidation state, Mn loses two electrons. Thus, the electron configuration becomes [Ar] 3d⁵.
Since H₂O is a weak field ligand, it doesn't cause pairing of electrons in the orbitals.
Step 3: Number of Unpaired Electrons
The 3d⁵ configuration has five unpaired electrons.
Step 4: Conclusion
The number of unpaired electrons in the complex is five.

Step 1: Oxide Basicity Trend
The basicity of an oxide generally increases as you move left across a period and decreases as you move down a group.
Titanium (Ti) has the most basic oxide among the elements given.
Step 2: Evaluate the options

• Option (1): Ti (Titanium): Titanium has the most basic oxide, TiO₂, due to its position in the periodic table (group 4).
• Option (2): V (Vanadium): Vanadium's oxide is less basic compared to Titanium.
• Option (3): Cr (Chromium): Chromium's oxide is acidic in nature.
• Option (4): Fe (Iron): Iron's oxide is amphoteric, meaning it exhibits both acidic and basic properties but is less basic than Titanium.

Step 3: Conclusion
Titanium forms the most basic oxide compared to the others.
Conclusion:

Ti forms the most basic oxide.

Step 1: Understanding Stainless Steel Composition
Stainless steel is an alloy made primarily from iron, chromium, nickel, and carbon. Let's break down each component:

1. Iron (Fe): Iron is the base metal in stainless steel. It provides the bulk structure and strength to the material. It is malleable and forms the core matrix of the alloy.
2. Chromium (Cr): Chromium is a crucial element in stainless steel. It is responsible for its corrosion resistance and durability. Typically, stainless steel contains at least 10.5% chromium by weight, which forms a protective oxide layer on the surface of the steel, preventing rust and oxidation.
3. Nickel (Ni): Nickel is added to stainless steel to enhance its strength and toughness. It also improves the steel's resistance to corrosion, especially in acidic or alkaline environments. Nickel gives stainless steel its characteristic shine and smooth texture.
4. Carbon (C): Carbon is used to increase the hardness of stainless steel. However, too much carbon can make the steel brittle. The amount of carbon is typically kept to a low level (less than 2%) to balance strength and ductility.

Step 2: Common Types of Stainless Steel
There are various grades of stainless steel, with the most common being 304 and 316 grades. Both contain iron, chromium (usually around 18-20%), nickel (8-10%), and small amounts of carbon. The specific proportions of these elements vary depending on the grade and desired properties.

• 304 Stainless Steel: The most commonly used stainless steel, known for its corrosion resistance and general-purpose strength. It typically contains 18% chromium and 8% nickel, with a low carbon content.
• 316 Stainless Steel: A higher-grade stainless steel with better resistance to chloride corrosion (ideal for marine environments). It contains 16-18% chromium, 10-14% nickel, and also includes 2-3% molybdenum.

Step 3: Conclusion
The correct answer is option (1), as iron, chromium, nickel, and carbon are the main constituents of stainless steel. Tungsten, vanadium, and other elements are sometimes included in specialized grades of steel, but they are not the primary components of standard stainless steel.
Conclusion:

Iron, chromium, nickel, and carbon

Step 1: Identify the metal oxides and their properties
The given metals are Titanium (Ti), Vanadium (V), Chromium (Cr), and Iron (Fe), each forming an oxide with varying basicity. Oxides of metals tend to be basic or acidic depending on the metal's position in the periodic table.
Step 2: Analyze the given options

• FeO (Iron(II) oxide): Iron(II) oxide is relatively basic but less so compared to Titanium oxides.
• VO (Vanadium monoxide): Vanadium oxides are typically less basic and more acidic.
• CrO (Chromium(II) oxide): Chromium oxides also have moderate basicity but are not the most basic of the options.
• TiO (Titanium(II) oxide): Titanium oxides are highly basic due to the low electronegativity and high metallic character of Titanium.

Step 3: Conclusion
Titanium oxide (TiO) is the most basic oxide among the options given, as Titanium is in a lower oxidation state and its oxide shows strong basic behavior.
Conclusion:

TiO is the most basic oxide.