Problem 44
Question
The basic character of the transition metal monoxides follow the order (a) \(\mathrm{CrO}>\mathrm{VO}>\mathrm{FeO}>\mathrm{TiO}\) (b) \(\mathrm{TiO}>\mathrm{VO}>\mathrm{CrO}>\mathrm{FeO}\) (c) \(\mathrm{TiO}>\mathrm{FeO}>\mathrm{VO}>\mathrm{CrO}\) (d) \(\mathrm{VO}>\mathrm{CrO}>\mathrm{TiO}>\mathrm{FeO}\)
Step-by-Step Solution
Verified Answer
The correct order is (b) \( \mathrm{TiO} > \mathrm{VO} > \mathrm{CrO} > \mathrm{FeO} \).
1Step 1: Understand the Concept
Transition metal monoxides are compounds formed with metals and oxygen (O). Their basic character is influenced by the oxidation state of the metal and the electronegativity of oxygen. The higher the oxidation state, the more acidic the oxide is and thus the lower the basic character.
2Step 2: Identify the Oxidation States
List the typical oxidation states of the metals in question:
- Ti in TiO is usually +2.
- V in VO has an oxidation state of +2.
- Cr in CrO also has +2.
- Fe in FeO is +2.
Since we are considering the basic character, recall that lower oxidation states correlate to increased basicity.
3Step 3: Analyze Trends
Considering that lower oxidation states correlate to higher basicity:
The given metals are in similar oxidation states (+2), comparing their size and electron configurations, metals earlier in the series like Ti and V tend to be more basic than Cr and Fe.
4Step 4: Order Based on Basicity
Given the oxidation states and typical periodic trends, order the monoxides based on increasing acidity or decreasing basicity:
Then the order of increasing basic character is:
1. TiO
2. VO
3. CrO
4. FeO
5Step 5: Find the Matching Option
Compare the derived basic character order with the provided options:
- (a) CrO > VO > FeO > TiO
- (b) TiO > VO > CrO > FeO
- (c) TiO > FeO > VO > CrO
- (d) VO > CrO > TiO > FeO
Option (b) matches the derived sequence.
Key Concepts
Oxidation StatesBasicity TrendsElectronegativity Influence
Oxidation States
In the realm of transition metal oxides, understanding oxidation states is fundamental. Oxidation state is a concept that describes the degree of oxidation (or loss of electrons) of an atom in a compound. For transition metals, these oxidation states can vary greatly, adding to their complexity and versatility.
Transition metals like Titanium (Ti), Vanadium (V), Chromium (Cr), and Iron (Fe) often form stable oxides, where each has a typical oxidation state of +2 in their monoxides. This is observed in TiO, VO, CrO, and FeO. Since these metals are all in the same oxidation state within these compounds, other factors like size and electron configuration influence their basicity. It's crucial to note that higher oxidation states generally correspond to more acidic oxides, whereas lower oxidation states often result in more basic ones.
This relationship helps in understanding why TiO is more basic than FeO, despite similarities in oxidation states, leading to unique trends in basicity seen in transition metal oxides.
Transition metals like Titanium (Ti), Vanadium (V), Chromium (Cr), and Iron (Fe) often form stable oxides, where each has a typical oxidation state of +2 in their monoxides. This is observed in TiO, VO, CrO, and FeO. Since these metals are all in the same oxidation state within these compounds, other factors like size and electron configuration influence their basicity. It's crucial to note that higher oxidation states generally correspond to more acidic oxides, whereas lower oxidation states often result in more basic ones.
This relationship helps in understanding why TiO is more basic than FeO, despite similarities in oxidation states, leading to unique trends in basicity seen in transition metal oxides.
Basicity Trends
Exploring the basicity trends of transition metal oxides reveals insightful patterns. Basicity refers to a compound's ability to behave as a base, often characterized by its tendency to accept protons or donate electrons.
Transition metal oxides that exhibit lower oxidation states typically have higher basicity. This is because such oxides can donate electrons more readily due to less effective nuclear charge and higher electron availability associated with a lower oxidation state. For instance, among the transition metal monoxides like TiO, VO, CrO, and FeO, the trend in basicity follows the series: TiO > VO > CrO > FeO.
Key reasons why basicity decreases in this sequence include:
Transition metal oxides that exhibit lower oxidation states typically have higher basicity. This is because such oxides can donate electrons more readily due to less effective nuclear charge and higher electron availability associated with a lower oxidation state. For instance, among the transition metal monoxides like TiO, VO, CrO, and FeO, the trend in basicity follows the series: TiO > VO > CrO > FeO.
Key reasons why basicity decreases in this sequence include:
- Ion size: Larger ions have more ionic character and are generally more basic.
- Metallic character: Metals on the left side of the periodic table tend to form more basic oxides.
- Number and type of bonding electrons: The nature of d-orbitals and the way they participate in bonding play a role in informing basicity.
Electronegativity Influence
Electronegativity is another factor that puts its fingerprint on the properties of transition metal oxides. It is a measure of an atom's ability to attract shared electrons in a chemical bond.
In transition metals, electronegativity influences how strongly they retain or surrender electrons, which directly affects the basicity or acidity of their oxides. Lower electronegativity typically means that the metal has a greater tendency to donate electrons, thus increasing the basic character of the oxide. Therefore, oxides such as TiO are more basic because Titanium has a comparatively low electronegativity, enabling it to donate electrons easily.
Yet, as we move across the transition metal series from Ti to Fe, the electronegativity tends to increase, explaining why FeO is less basic than TiO. So, understanding how electronegativity values shift is crucial to predicting and rationalizing the basicity trends seen in these compounds.
By digesting these aspects of oxidation states, basicity trends, and electronegativity influence together, a clearer picture of transition metal oxides emerges.
In transition metals, electronegativity influences how strongly they retain or surrender electrons, which directly affects the basicity or acidity of their oxides. Lower electronegativity typically means that the metal has a greater tendency to donate electrons, thus increasing the basic character of the oxide. Therefore, oxides such as TiO are more basic because Titanium has a comparatively low electronegativity, enabling it to donate electrons easily.
Yet, as we move across the transition metal series from Ti to Fe, the electronegativity tends to increase, explaining why FeO is less basic than TiO. So, understanding how electronegativity values shift is crucial to predicting and rationalizing the basicity trends seen in these compounds.
By digesting these aspects of oxidation states, basicity trends, and electronegativity influence together, a clearer picture of transition metal oxides emerges.
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