Explain types of hybridisation, shapes and Number of lone pairs on the central atom of the following molecules. 3) SF4
Answers
Answer:
D
Different, with 1,0 and 2
Molecule No. of bond angles No. of lone pairs Hybridisation Shape
SF
4
4 1 sp
3
d Irregular tetrahedral
CF
4
4 - sp
3
tetrahedral
XeF
4
4 2 sp
3
d
2
square planar
Answer:
Explanation:What is Hybridization?
Scientist Pauling introduced the revolutionary concept of hybridization in the year 1931. He described it as the redistribution of the energy of orbitals of individual atoms to give new orbitals of equivalent energy and named the process as hybridisation. In this process, the new orbitals come into existence and named as the hybrid orbitals.
Rules for Observing the Type of Hybridisation
The following rules are observed to understand the type of hybridisation in a compound or an ion.
Calculate the total number of valence electrons.
Calculate the number of duplex or octet OR
Number of lone pairs of electrons
Number of used orbital = Number of duplex or octet + Number of lone pairs of electrons
If there is no lone pair of electrons then the geometry of orbitals and molecule is different.
Types of Hybridisation
The following are the types of hybridisation:
1) sp – Hybridisation
In such hybridisation one s- and one p-orbital are mixed to form two sp – hybrid orbitals, having a linear structure with bond angle 180 degrees. For example in the formation of BeCl2, first be atom comes in excited state 2s12p1, then hybridized to form two sp – hybrid orbitals. These hybrid orbitals overlap with the two p-orbitals of two chlorine atoms to form BeCl2
2) sp2 – Hybridisation
In such hybridisation one s- and to p-orbitals are mixed form three sp2– hybrid orbitals, having a planar triangular structure with bond angle 120 degrees.
3) sp3 – Hybridisation
In such hybridisation one s- and three p-orbitals are mixed to form four sp3– hybrid orbitals having a tetrahedral structure with bond angle 109 degrees 28′, that is, 109.5 degrees.
hybridisation
Studying the Formation of Various Molecules
1) Methane
4 equivalent C-H σ bonds can be made by the interactions of C-sp3 with an H-1s
2) Ethane
6 C-H sigma(σ) bonds are made by the interaction of C-sp3 with H-1s orbitals and 1 C-C σ bond is made by the interaction of C-sp3 with another C-sp3 orbital.
3) Formation of NH3 and H2O molecules
In NH2 molecule nitrogen atom is sp3-hybridised and one hybrid orbital contains two electrons. Now three 1s- orbitals of three hydrogen atoms overlap with three sp3 hybrid orbitals to form NH3 molecule. The angle between H-N-H should be 109.50 but due to the presence of one occupied sp3-hybrid orbital the angle decreases to 107.80. Hence, the bond angle in NH3 molecule is 107.80.
4) Formation of C2H4 and C2H2 Molecules
In C2H4 molecule carbon atoms are sp2-hybridised and one 2p-orbital remains out to hybridisation. This forms p-bond while sp2 –hybrid orbitals form sigma- bonds.
5) Formation of NH3 and H2O Molecules by sp2 hybridization
In H2O molecule, the oxygen atom is sp3 – hybridized and has two occupied orbitals. Thus, the bond angle in the water molecule is 105.50.
A Solved Question for You
Q: Discuss the rules of hybridisation. Are they important to the study of the concept as a whole?
Ans: Yes, the rules of hybridisation are very important to be studied before diving into the subject of hybridisation. Hence, these rules are essential to the understanding of the concepts of the topic. The following are the rules related to hybridisation:
Orbitals of only a central atom would undergo hybridisation.
The orbitals of almost the same energy level combine to form hybrid orbitals.
The numbers of atomic orbitals mixed together are always equal to the number of hybrid orbitals.
During hybridisation, the mixing of a number of orbitals is as per requirement.
The hybrid orbitals scattered in space and tend to the farthest apart.
Hybrid bonds are stronger than the non-hybridised bonds.
hope its help you