Organometallic Chemistry and Main Group Trends

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Questions and Answers

Which compound is more stable towards hydrolysis?

Both are equally stable

Neither compound is stable

CCl4 (correct)

SiCl4

What primarily determines the relative basicity of a compound?

pKa values (correct)

Strength of E-O bond

Size of the atoms

Electronegativity of atoms involved

What is the main reason for the difference in reactivity towards hydrolysis between CCl4 and SiCl4?

Storage conditions for each compound

The size of silicon atoms

Kinetic inertness of CCl4 (correct)

The bond strength of Si-Cl is weaker than C-Cl

Which of the following is a correct statement about nucleophilicity?

Nucleophilicity is measured by the rate of reaction Signup and view all the answers

Based on bond enthalpies, which compound is thermodynamically less stable with respect to hydrolysis?

SiCl4 Signup and view all the answers

Which bond is considered the most ionic and why?

CsF, due to greater electronegativity difference Signup and view all the answers

Which of the following describes a Lewis base?

A substance that donates electron pairs Signup and view all the answers

Which of the following is identified as a Lewis acid?

BF3 Signup and view all the answers

Which order correctly ranks the listed elements from least to most electronegative?

Cs, Ba, Mg, Zn, B, O, F Signup and view all the answers

What is the correct order of the elements from smallest to largest radius?

F, O, B, Zn, Mg, Ba, Cs Signup and view all the answers

Which bond type is primarily characterized by the interaction between main-group elements and carbon?

E-C σ bonds Signup and view all the answers

What is the method used to measure the distance (d) between an element and carbon in a bond?

X-ray crystallography Signup and view all the answers

Given an In-C bond length of 223 pm, how is the covalent radius of Indium typically calculated?

By subtracting the covalent radius of C from the bond length Signup and view all the answers

What is the covalent radius of In?

146 pm Signup and view all the answers

Which hybridization results in the smallest effective radius for carbon?

sp Signup and view all the answers

Which of the following elements has a lower electronegativity than carbon?

Si Signup and view all the answers

What is the bond length of R2C=CR2?

136 pm Signup and view all the answers

Which statement about electronegativity is true?

Electronegativity values for carbon in sp3, sp2, and sp order are 2.5, 2.75, and 3.29 respectively. Signup and view all the answers

Which of the following compounds is classified as unstable?

Sn(CH3)4 Signup and view all the answers

For which bonding type does the effective covalent radius decrease?

Multiple covalent bonding Signup and view all the answers

What is the bond length of R3C-CR3?

154 pm Signup and view all the answers

Which electron-attracting tendency is attributed to a high electronegativity in carbon?

Increases with s character Signup and view all the answers

Among the following elements, which has the highest electronegativity?

F Signup and view all the answers

Study Notes

Organometallic Chemistry

Organometallic compounds contain a bond between a metal (M) or a main-group element (E) and carbon.
E-C sigma bonds are common, while E=C bonds are less common.
The chemistry of organometallic compounds is heavily influenced by the specific properties of the main-group element (E).
Size and electronegativity of E are key factors in determining the stability, reactivity and bond type of organometallic compounds.

Main Group Trends and E-C Bond Lengths

Electronegativity generally increases across a period and decreases down a group.
Atomic size generally increases down a group and decreases across a period.
The covalent radius of an element can be calculated using the bond length and the covalent radius of carbon.
E refers to a main group element.
The covalent radius can vary depending on the type of bonding. The covalent radius of Carbon is related to its hybridization (sp3, sp2, sp).

Effects of Electronegativity and Hybridization

The electronegativity of carbon is 2.5.
Carbon is more electronegative than most metals but less electronegative than N, O, F, Cl, Br, and I.
All organometallics are polar, with the metal or main-group element having a partial positive charge and carbon having a partial negative charge.
The electronegativity of carbon changes with hybridization and increases as s character increases: sp3 < sp2 < sp.
Increased s character results in increased acidity of C-H bonds.

Reactivity and Thermodynamics of Organometallics

Main-group organometallic compounds are often thermodynamically unstable due to their susceptibility to oxidation.
The reactivity and stability of organometallic compounds towards water are influenced by bond strengths and electronegativity differences.
C-Cl bonds are weaker than C-O bonds, making CCl4 thermodynamically unstable towards hydrolysis, but kinetically inert.
Si-Cl bonds are weaker than Si-O bonds, resulting in SiCl4 being thermodynamically unstable and kinetically labile towards hydrolysis.

Basicity vs Nucleophilicity

Basicity is a thermodynamic property that describes a base's ability to donate electrons to a proton. Higher pKa values indicate stronger bases.
Nucleophilicity is a kinetic property that reflects the ability of a nucleophile to donate electrons to an electrophile. Faster reaction rates indicate stronger nucleophiles.
Strong bases do not always equate to strong nucleophiles. Steric hindrance and solvation can significantly impact the reactivity of a given nucleophile.

Common Solvents

Non-polar solvents are generally used for reactions with non-polar organometallic compounds.
Polar protic solvents are more polar and have a hydrogen atom attached to an electronegative atom.
Polar aprotic solvents are polar but do not have a hydrogen atom attached to a highly electronegative atom.
Choice of solvent is important in organometallic chemistry as it can affect the reactivity of the organometallic compound.

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Description

Explore the intriguing world of organometallic compounds, focusing on the crucial bond between metals and carbon. This quiz delves into the trends of electronegativity and atomic size, as well as their effects on bond lengths and stability of these compounds. Perfect for chemistry enthusiasts looking to deepen their understanding of main-group elements in organometallic contexts.