Molecular Geometry MCQ Quiz in தமிழ் - Objective Question with Answer for Molecular Geometry - இலவச PDF ஐப் பதிவிறக்கவும்

Concept:

Polar and non-polar molecules - Polarity is the distribution of charge over the atoms of a molecule joined by a bond.

• Based on polarity molecules are divided into two categories - polar and non-polar.
• The molecules with differences in the electronegativities of their atom are having some net dipole moment and are called polar molecules.
• Non-polar molecules have a net dipole moment of zero as the dipole moment of exactly opposite bonds in the molecule cancel each other.

Explanation:

• Nonpolar molecules are those which has a net dipole moment of zero.
• As dipole moment is a vector quantity, the overall dipole moment of a molecule is the sum of dipoles of all the bonds present in the molecule.
• Thus the exactly equal and opposite bonds constitute a net dipole zero.

The calculation for net dipole moment in given molecules - 

SbCl₅ : 

SbCl₅ has trigonal bipyramidal geometry having axial and equatorial bonds. It has a net dipole moment of zero as - 

• Axial bonds have a bond angle of 180° which constitutes two exactly equal and opposite bonds. Hence dipole moment is zero.
• Equatorial bonds also have net dipole zero as the dipole moment of one equatorial Sb-Cl bond is the resultant of the vector sum of the other two equatorial Sb-Cl bonds.

So, the net vector summation of bond moments will be zero so SbCl₅ is a non-polar molecule.

In the other given molecules, the net dipole moment is not zero because -

• In NO₂, there is non-symmetry in the structure.
• In POCl₃, there is a difference in electronegativity of Cl and O atoms.
• In CH₂O, O atom is more highly electronegative than the H atom.

Thus, the only nonpolar molecule is SbCl5.

Hence, the correct answer is Option 2.

Concept:

VSEPR Theory

• The shape of the molecule is determined by repulsions between all of the electrons present in the valence shell.
• Electron pairs in the valence shell of the central atom repel each other and align themselves to minimize this repulsion.
• Lone pairs of the electron on the central atom repeal the most. i.e., Lone pair -lone pair repulsion > lone pair-bond pair > bond pair-bond pair.
• The valence shell electron pairs arrange themselves in space as far as possible to minimize mutual repulsion.

Explanation:

ClF₃

• In ClF₃, there are 5 electron pairs around Cl. In which 3 are bonding pairs and 2 are non-bonding pairs.
• Here, Repulsion is minimized by placing the five electron groups at angles of 120° and 90° which is a trigonal bipyramidal arrangement.
• The two non-bonding pairs are on the trigonal plane. So, these two equatorial lone pairs making the final structure T-shaped.

According to VSEPR theory, ClF₃ molecules possess T-shape.

Concept:

The geometry of a molecule:

• The geometry of a molecule depends on the arrangement of bonds about its centre in space.
• The arrangement further depends on the type of hybridization the centre atom is undergoing.
• The orientation of the hybrid orbitals is different in different cases.
• As bonds are formed via overlap of these orbitals, the bonds have directional nature.
• Therefore, hybridization is directly linked to the geometry of the molecule.

Hybridization and bond angles:

• According to VSEPR theory, the electron groups arrange themselves around each other so as to minimize repulsion.
• The electron group includes the bond pairs as well as lone pairs of electrons.
• If repulsion is more, the energy of the system is raised and the molecule becomes unstable.
• So, the arrangement in which there is minimum repulsion and maximum attraction is the most stable structure.
• The arrangement in space gives some angles between the central atom and the bonded atoms which are known as the bond angles.

Few types of hybridization, their modes of mixing, and geometry of molecules are-

Explanation:

• In CO, the structure is:
  : C ≡ O :
• There exist three bonds between carbon and oxygen out of which one is sigma and two are pi.
• So, two pi bond corresponds to 'sp' hybridization.
• The sigma bond between the two atoms is made by the head-on overlap of 2p - 2p orbitals of Carbon and Oxygen.
• The pi bonds are formed by the lateral overlap between p orbitals of carbon and oxygen.

Hence, the mode of hybridization of carbon in CO is 'sp'.

Additional Informationsp Hybridisation of carbon:

• The bond between two C atoms includes two pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• One sigma bond exists between each carbon and hydrogen.
• A total of two sigma bonds means sp hybridization and linear geometry.

sp² Hybridisation of carbon:

• The bond between two C atoms includes one pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• This type of hybridization is seen in alkenes.
• The geometry is trigonal planar.

sp³ Hybridisation of carbon:

• Only sigma bonds are formed by the carbon atoms.
• The geometry is tetrahedral.

Concept:

The geometry of a molecule:

• The geometry of a molecule depends on the arrangement of bonds about its centre in space.
• The arrangement further depends on the type of hybridization the centre atom is undergoing.
• The orientation of the hybrid orbitals is different in different cases.
• As bonds are formed via overlap of these orbitals, the bonds have directional nature.
• Therefore, hybridization is directly linked to the geometry of the molecule.

Hybridization and bond angles:

• According to VSEPR theory, the electron groups arrange themselves around each other so as to minimize repulsion.
• The electron group includes the bond pairs as well as lone pairs of electrons.
• If repulsion is more, the energy of the system is raised and the molecule becomes unstable.
• So, the arrangement in which there is minimum repulsion and maximum attraction is the most stable structure.
• The arrangement in space gives some angles between the central atom and the bonded atoms which are known as the bond angles.

Few types of hybridization, their modes of mixing, and geometry of molecules are-

Explanation:

• In CO, the structure is:
  : C ≡ O :
• There exist three bonds between carbon and oxygen out of which one is sigma and two are pi.
• So, two pi bond corresponds to 'sp' hybridization.
• The sigma bond between the two atoms is made by the head-on overlap of 2p - 2p orbitals of Carbon and Oxygen.
• The pi bonds are formed by the lateral overlap between p orbitals of carbon and oxygen.

Hence, the mode of hybridization of carbon in CO is 'sp'.

Additional Informationsp Hybridisation of carbon:

• The bond between two C atoms includes two pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• One sigma bond exists between each carbon and hydrogen.
• A total of two sigma bonds means sp hybridization and linear geometry.

sp² Hybridisation of carbon:

• The bond between two C atoms includes one pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• This type of hybridization is seen in alkenes.
• The geometry is trigonal planar.

sp³ Hybridisation of carbon:

• Only sigma bonds are formed by the carbon atoms.
• The geometry is tetrahedral.

The correct answer is N2

Concept:-

• Bond order: Bond order is a measure of the strength of a chemical bond.
• Lewis structure: A Lewis structure is a diagram that shows the arrangement of electrons in a molecule.
• Bonding electrons: Bonding electrons are the electrons that are involved in forming a chemical bond.
• Antibonding electrons: Antibonding electrons are the electrons that are not involved in forming a chemical bond.

Explanation:-

Bond order is a measure of the strength of a chemical bond. It is calculated as half the difference between the number of bonding electrons and the number of antibonding electrons.

To determine which molecule has the largest bond order, we need to calculate the bond order for each molecule.

C₂: 
Lewis structure: C::C
Number of bonding electrons: 2
Number of antibonding electrons: 0
Bond order = (2 - 0) / 2 = 1
O₂:
Lewis structure: O=O
Number of bonding electrons: 4
Number of antibonding electrons: 2
Bond order = (6 - 2) / 2 = 2
N₂:
Lewis structure: N≡N
Number of bonding electrons: 6
Number of antibonding electrons: 2
Bond order = (10 - 4) / 2 = 3
F₂:
Lewis structure: F-F
Number of bonding electrons: 2
Number of antibonding electrons: 0
Bond order = (2 - 0) / 2 = 1
Conclusion:-

Therefore, the molecule with the largest bond order is N₂.

The correct answer is sp3d

Concept:-

• Hybridization: This is a fundamental concept in molecular chemistry denoting the combination of atomic orbitals to form new hybrid orbitals. Hybridization helps predict molecular shape and bonding properties.
• Lewis Structures and electron domain theory: Lewis structures show the arrangement of electrons in a molecule, including the bonding pairs of electrons between atoms and the lone pairs on individual atoms. These electron domains (areas around the central atom where electrons are most likely to be found, encompassing both bonding electrons and lone pairs) inform the hybridization of a molecule.
• VSEPR Theory: Valence Shell Electron Pair Repulsion (VSEPR) Theory is used to predict the geometry of molecules based on the number of electron domain (bonding and non-bonding pairs) around a central atom. It states that these domains arrange themselves in a manner that minimizes repulsion.
• Steric Number: It's a term used for the sum of sigma bonds (single bonds) and lone pairs of electrons around the central atom in a molecule. It helps to determine the hybridization and molecular geometry based on the VSEPR (Valence Shell Electron Pair Repulsion) theory. Specifically, the steric number helps us structure how these different electron domains will arrange themselves in space.

Explanation:-

• If the steric number is 2, the molecular shape is linear, and the hybridization is sp.
• If the steric number is 3, the molecular shape is trigonal planar, and the hybridization is sp2.
• If the steric number is 4, the molecular shape is tetrahedral, and the hybridization is sp3.
• If the steric number is 5, the molecular shape could be trigonal bipyramidal, seesaw, or T-shaped, and the hybridization is sp3d.
• If the steric number is 6, the molecular shape could be octahedral, square pyramidal, or square planar, and the hybridization is sp3d2.

In our ClF₃ example, Cl (the central atom) forms three single bonds with F atoms and it also has two lone pairs. These 5 electron domains (3 bonds + 2 lone pairs) give Cl a steric number of 5.

As per VSEPR theory, a central atom with a steric number of 5 adopts a trigonal bipyramidal arrangement to minimize electron pair repulsion. From this, we conclude its hybridization to be sp³d.

option 3) "sp3d", making this the correct response to the question

Concept:

The geometry of a molecule:

• The geometry of a molecule depends on the arrangement of bonds about its centre in space.
• The arrangement further depends on the type of hybridization the centre atom is undergoing.
• The orientation of the hybrid orbitals is different in different cases.
• As bonds are formed via overlap of these orbitals, the bonds have directional nature.
• Therefore, hybridization is directly linked to the geometry of the molecule.

Hybridization and bond angles:

• According to VSEPR theory, the electron groups arrange themselves around each other so as to minimize repulsion.
• The electron group includes the bond pairs as well as lone pairs of electrons.
• If repulsion is more, the energy of the system is raised and the molecule becomes unstable.
• So, the arrangement in which there is minimum repulsion and maximum attraction is the most stable structure.
• The arrangement in space gives some angles between the central atom and the bonded atoms which are known as the bond angles.

Few types of hybridization, their modes of mixing, and geometry of molecules are-

Explanation:

• In CO, the structure is:
  : C ≡ O :
• There exist three bonds between carbon and oxygen out of which one is sigma and two are pi.
• So, two pi bond corresponds to 'sp' hybridization.
• The sigma bond between the two atoms is made by the head-on overlap of 2p - 2p orbitals of Carbon and Oxygen.
• The pi bonds are formed by the lateral overlap between p orbitals of carbon and oxygen.

Hence, the mode of hybridization of carbon in CO is 'sp'.

Additional Informationsp Hybridisation of carbon:

• The bond between two C atoms includes two pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• One sigma bond exists between each carbon and hydrogen.
• A total of two sigma bonds means sp hybridization and linear geometry.

sp² Hybridisation of carbon:

• The bond between two C atoms includes one pi and one sigma.
• A pi bond is formed by pure p-p overlap.
• This type of hybridization is seen in alkenes.
• The geometry is trigonal planar.

sp³ Hybridisation of carbon:

• Only sigma bonds are formed by the carbon atoms.
• The geometry is tetrahedral.

Concept:

Hybridization:

→ The process of intermixing the orbitals of slightly different energies so as to redistribute their energies, resulting in the formation of a new set of orbitals of equivalent energies and shape.

For example, when one 2s and three 2p-orbitals of carbon hybridize, there is the formation of four new sp³ hybrid orbitals.

Types of hybridisation : sp , sp² , sp³ , sp³d , sp³d²  and sp³d³ .

Explanation:

→ PCl₅ : P configuration is 1s² 2s² 2p⁶ 3s² 3p³ . it is in the ground state. 

Excited configuration is 1s2 2s2 2p6 3s¹ 3p³ 3d¹ here 3s1 3p3 3d¹ are 5 half filled orbitals having almost the same energy will intermix and form new 5 hybrid orbitals of hybridisation sp³d. hence geometry is Trigonal bipyramidal.

→ SF₆  : S ground state configuration is 1s2 2s2 2p6 3s2 3p⁴ .

Excited configuration is 1s2 2s2 2p6 3s1 3p3 3d² here 3s1 3p3 3d² are 6  half filled orbitals having almost same energy will intermix and form new 6 hybrid orbitals of hybridisation sp3d². hence geometry is Octahedral.

→ BrF₅ : Br ground state configuration is [Ar] 3d¹⁰ 4s² 4p⁵ .

Excited state configuration is  [Ar] 3d10 4s2 4p³ 4d² .

Here 1 full filled and 5 half filled orbitals (total 6) having almost the same energy will hybridise with each other. This intermixing will form  sp3d² hybridization. 1 sp3d² orbital will occupy the lone pair and the other 5 will be occupied by F.

So here 5 bond pairs and one lone pair hence its shape is square pyramidal.

→ BF₃ : B  ground state configuration is 1s2 2s2 2p¹ .

Excited configuration is 1s2 2s¹ 2p² . Here 2s¹ 2p² are 3 half-filled orbitals having almost the same energy that will intermix and form new 3 hybrid orbitals of hybridization sp².

Hence geometry is Trigonal planar.

Hence answer is Option 2

Correct answer: 1)

Concept:

• Hybridization is the phenomenon of combining two atomic orbitals to give a new degenerate hybrid orbital that has the same energy levels.
• Hybridization increases the stability of bond formation more than unhybridized orbitals.
• We can predict the shape of molecules by their hybridization.
• The following rules are observed to understand the type of hybridization in a compound or an ion.
  • Calculate the total number of valence electrons.
  • Calculate the number of duplexes or octet or
  • Number of lone pairs of electrons
  • Number of used orbital = Number of duplexes or octet + Number of lone pairs of electrons
  • If there is no lone pair of electrons then the geometry of orbitals and molecules is different.

Explanation:

• Hybrid orbital can be calculated as: 
• Here, the central atom of chlorine has 7 valence electrons and oxygen is a divalent atom so no monovalent atom is present. 
• In no cationic charge. Only a -1 charge is present on anion.
• By putting these values on the above equation, we get

=4

• According to the VSEPR theory, the electron clouds on atoms and the single electron pair surrounding chlorine will repel each other.
• They'll be forced apart.
• As a result, they give the molecule will be a trigonal pyramidal in shape." id="MathJax-Element-71-Frame" role="presentation" style="position: relative;" tabindex="0">
• As the number of hybrid orbitals in Chlorate ion is Four, so there will be one s and three p orbital.
• The hybridization of chlorate ion is sp³.

Conclusion:

Thus, the hybrid state of Cl in  is sp³.