Bond length is the experimentally determined average distance between two bonded atoms. Bonded atoms vibrate due to thermal energy available in the surroundings. Bond lengths are typically in the range of 100 - 200 pm ( 1 -2 A ∘ ) . As a general trend, atomic radius decreases across a row in the periodic table and increases down a group. Atoms with multiple bonds between them have shorter bond lengths than singly bonded ones.

Using data from the table, answer the following : Examples C 2 H 6 Ethane C 2 H 4 Ethene C 2 H 2 Ethyne Structure - C / ∖ - C ∖ / - C / ∖ = C ∖ / - C ≡ C - Type of bond between carbons single double triple Bond length (nm) 0 . 154 0 . 134 0 . 120 Bond enthalpy KJ mol - 1 348 612 837 What happens to the bond length when unsaturation increases?

Bond length is inversely proportional to % S character or extent of unsaturation. So ethane has lowest % S character so it has highest bond length and ethyne has highest % S character( sp hybridisation) so it has lowest bond length. Ethane> Ethene> Ethyne (Bond length)

Using data from the table, answer the following : Examples C 2 H 6 Ethane C 2 H 4 Ethene C 2 H 2 Ethyne Structure - C / ∖ - C ∖ / - > C = C < - C ≡ C - Type of bond between carbons single double triple Bond length (nm) 0 . 154 0 . 134 0 . 120 Bond enthalpy KJ mol - 1 348 612 837 Which is the most stable compound?

Among the organic compounds, triple covalent bonds are less stable than double bonds, and double bonds are less stable than single bonds. In a triple bond and in the double bond there will be six and four electrons respectively trying to occupy a small space in between the two carbon atoms of ethyne and ethene. The electrons repel one another due to similar charge making them unstable. The single bond is the most stable, hence the least reactive because the two electrons are comfier in their orbitals. Going by this logic, ethane is the most stable compound among the given compounds.

Using data from the table, answer the following : Examples C 2 H 6 Ethane C 2 H 4 Ethene C 2 H 2 Ethyne Structure - C / ∖ - C ∖ / - C / ∖ = C ∖ / - C ≡ C - Type of bond between carbons single double triple Bond length (nm) 0 . 154 0 . 134 0 . 120 Bond enthalpy KJ mol - 1 348 612 837 Indicate the relation between bond strength and bond enthalpy.

Bond enthalpy describes the amount of energy stored in a bond between atoms in a molecule. According to table, bond enthalpy is directly proportional to bond strength. As the number of bonds between two atoms increase, bond strength also increases.

Using data from the table, answer the following : Examples C 2 H 6 Ethane C 2 H 4 Ethene C 2 H 2 Ethyne Structure Type of bond between carbons single double triple Bond length (nm) 0.154 0.134 0.120 Bond Enthalpy kJ mol - 1 348 612 837 Comment on overall relation between bond length, bond enthalpy and bond strength and stability.

Generally, as the bond energy increases, the bond length decreases. The strength of a bond between two atoms increases as the number of lone pairs in the bond increases. Hence, the stability of the molecule increases. Stability α Bond strength α Bond enthalpy α 1 Bond length

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Define bond length.

Important Questions on Chemical Bonding

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 3

Predict the shape and bond angles in the following molecules: ${CF}_{4}$ .

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 3

Predict the shape and bond angles in the following molecule: ${NF}_{3}$ .

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 3

Predict the shape and bond angles in the molecule: $HCN$ .

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 3

Predict the shape and bond angle in the following molecule: $H_{2} S$ .

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 4

Using data from the table, answer the following :

Examples	$C_{2} H_{6}$ Ethane	$C_{2} H_{4}$ Ethene	$C_{2} H_{2}$ Ethyne
Structure	$- {}_{/}^{∖}C - C_{∖}^{/} -$	${}_{/}^{∖}C = C_{∖}^{/}$	$- C \equiv C -$
Type of bond between carbons	single	double	triple
Bond length (nm)	$0.154$	$0.134$	$0.120$
Bond enthalpy $KJ {mol}^{- 1}$	$348$	$612$	$837$

What happens to the bond length when unsaturation increases?

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 4

Using data from the table, answer the following :

Examples	$C_{2} H_{6}$ Ethane	$C_{2} H_{4}$ Ethene	$C_{2} H_{2}$ Ethyne
Structure	$- {}_{/}^{∖}C - C_{∖}^{/} -$	$> C = C <$	$- C \equiv C -$
Type of bond between carbons	single	double	triple
Bond length (nm)	$0.154$	$0.134$	$0.120$
Bond enthalpy $KJ {mol}^{- 1}$	$348$	$612$	$837$

Which is the most stable compound?

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11th Maharashtra Board

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Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 4

Using data from the table, answer the following :

Examples	$C_{2} H_{6}$ Ethane	$C_{2} H_{4}$ Ethene	$C_{2} H_{2}$ Ethyne
Structure	$- {}_{/}^{∖}C - C_{∖}^{/} -$	${}_{/}^{∖}C = C_{∖}^{/}$	$- C \equiv C -$
Type of bond between carbons	single	double	triple
Bond length (nm)	$0.154$	$0.134$	$0.120$
Bond enthalpy $KJ {mol}^{- 1}$	$348$	$612$	$837$

Indicate the relation between bond strength and bond enthalpy.

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11th Maharashtra Board

IMPORTANT

Chemistry>Chapter 5 - Chemical Bonding>Exercises>Q 4

Using data from the table, answer the following :

Examples	$C_{2} H_{6} Ethane$	$C_{2} H_{4} Ethene$	$C_{2} H_{2} Ethyne$
Structure
Type of bond between carbons	single	double	triple
Bond length (nm)	0.154	0.134	0.120
Bond Enthalpy $kJ {mol}^{- 1}$	348	612	837

Comment on overall relation between bond length, bond enthalpy and bond strength and stability.

Define bond length.

Important Questions on Chemical Bonding

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