By Team Aakash Byju's | 24th January 2023
The electronic configuration of 'Be' in the ground state is 1s 2s . Since there are no unpaired electrons, it is excited by promoting one of its 2s electrons into an empty 2p orbital.
Example 1: Beryllium Chloride (BeCl )
2
Ground state :
Excited state:
1s
2s
2p
2
2
2
2
In the excited state, the electronic configuration of Be is 1s 2s 2p .
Excited state:
1s
2s
2p
2
1
1
2
1
1
The excited beryllium atom undergoes 'sp' hybridization by combining two 2s and one 2p orbital. As a result, two half-filled 'sp' hybrid orbitals are formed and aligned linearly.
2s
2p
energy
sp hybridisation
Two σ bonds are formed by half-filled sp-orbitals with two 'Cl' atoms. BeCl forms a linear shape with a bond angle of 180.
Be
2
o
Cl
Cl
The electronic configuration of 'C' is 1s 2s 2p 2p . Since there are only two unpaired electrons, carbon promotes one of its 2s electrons into the empty 2p orbital in the excited state.
Example 2: Acetylene (C H )
2
2
2
2
1
x
y
1
z
H
H
C
C
In the excited state, the electronic configuration of C is 1s 2s 2p 2p 2p .
Excited state:
2s
2p
x
2p
y
2p
z
1
1
1
1
1s
2
2
1
1
x
1
y
z
1
c:
1s
2s
2p
x
2p
y
2p
z
In the excited state, each carbon atom undergoes 'sp' hybridization, which results in two half-filled 'sp' orbitals that are aligned linearly.
sp Hybridised state:
c=
1s
2s
2p
x
2p
y
2p
z
sp Hybrid orbital
un Hybrid orbital
Each carbon forms a σ bond with the hydrogen atom. Acetylene forms a linear shape with a bond angle of 180.
o
H
H
C
C
sp-s