Chapter 1.7: A Combined Valence Bond and Molecular Orbital Theory Approach to Covalent Bonding

Question 1

Define  Sigma (σ) bonding molecular orbital

Answer 1

a molecular orbital in which electron density is concentrated between two nuclei; along the axis joining them, and is cylindrically symmetrical

Question 2

Define molecular orbital (MO) theory

Answer 2

a theory of chemical bonding in which electrons in molecules occupy molecular orbitals that extend over the entire molecules and are formed by the combination of the atomic orbitals that make up the molecule

Question 3

What is a state of a system at higher energy than the ground state?

Answer 3

excited state

Question 4

Define antibonding molecular orbital

Answer 4

a molecular orbital in which electrons have a higher energy than they would in isolated atomic orbitals

Question 5

Define sp2 hybrid orbital

Answer 5

• a hybrid atomic orbital formed by the combination of one s orbital and two 2p atomic orbitals

Question 6

Define  pi (п) bonding molecular orbital

Answer 6

a covalent bond formed by the overlap of parallel 2p orbitals
• lack of electron density along bond axis
• breaks if rotated 90°

Question 7

Define ground state

Answer 7

the lowest energy state of a system

Question 8

Define excited state

Answer 8

a state of a system at higher energy than the ground state

Question 9

What is a theory of chemical bonding in which electrons in molecules occupy molecular orbitals that extend over the entire molecules and are formed by the combination of the atomic orbitals that make up the molecule?

Answer 9

molecular orbital (MO) theory

Question 10

What is the lowest energy state of a system?

Answer 10

ground state

Question 11

What is a molecular orbital in which electrons have a higher energy than they would in isolated atomic orbitals?

Answer 11

antibonding molecular orbital

Question 12

What is - a hybrid atomic orbital formed by the combination of one s orbital and two 2p atomic orbitals?

Answer 12

sp2 hybrid orbitals

Question 13

What is a hybrid atomic orbital formed by the combination of one s atomic orbital and two 2p atomic orbitals?

Answer 13

sp hybrid orbital

Question 14

What is a hybrid atomic orbital formed by the combination of one s atomic orbital and three 2p atomic orbitals?

Answer 14

sp3 hybrid orbitals

Question 15

What is a molecular orbital in which electron density is concentrated between two nuclei; along the axis joining them, and is cylindrically symmetrical?

Answer 15

 Sigma (σ) bonding molecular orbital

Question 16

Define hybrid orbital

Answer 16

an orbital formed by the combination of two or more atomic orbitals

Question 17

Define bonding molecular orbital

Answer 17

a molecular orbital in which electrons have a lower energy than they would in isolated atomic orbitals

Question 18

Define sp hybrid orbital

Answer 18

a hybrid atomic orbital formed by the combination of one s atomic orbital and two 2p atomic orbitals

Question 19

Define sp3 hybrid orbitals

Answer 19

a hybrid atomic orbital formed by the combination of one s atomic orbital and three 2p atomic orbitals

Question 20

What is an orbital formed by the combination of two or more atomic orbitals?

Answer 20

hybrid orbitals

Question 21

Define hybridization

Answer 21

the combination of atomic orbitals of different types

Question 22

What is the combination of atomic orbitals of different types?

Answer 22

hybridization

Question 23

What is a molecular orbital in which electrons have a lower energy than they would in isolated atomic orbitals?

Answer 23

bonding molecular orbital

Question 24

What is a model of bonding that places electron pairs between adjacent atoms to create bonds?

Answer 24

valence bond theory

Question 25

What is a covalent bond formed by the overlap of parallel 2p orbitals
• lack of electron density along bond axis
• breaks if rotated 90°
?

Answer 25

 pi (п) bonding molecular orbital

Question 26

Define valence bond theory

Answer 26

a model of bonding that places electron pairs between adjacent atoms to create bonds