chemistry chapter 3: chemical bonds

Question 1

ionic bonds are formed when electronegativity difference is

Answer 1

equals to or greater than 1.7

Question 2

define bond energy

Answer 2

bond energy can be defined as the average amount of energy required to break all bonds of a particular type in one mole of a substance. also called bond enthalpy, measured in KJ/mole. multiple, sigma and polar covalent bonds have high bond energy.

Question 3

define electronegativity?

Answer 3

tendency of an atom of a molecule to attract a shared pair of e- towards itself.

Question 4

relation of bond energy and atoms size

Answer 4

small size atoms have higher bond energy due to high inter atomic attraction.

Question 5

relation of bond energy and bond length

Answer 5

smaller the bond length higher the bond energy

Question 6

define bond length

Answer 6

Bond length is defined as the equilibrium distance between the nuclei of two bonded atoms in a molecule.

Question 7

bond energy is a measure of….

Answer 7

bond strength

Question 8

relation of bond energy and E.N difference

Answer 8

as bond energy increases that means that the E.N difference is also large

Question 9

What are the main types of chemical bonds?

Answer 9

The main types of chemical bonds are:
Ionic bond
Covalent bond
Metallic bond

Question 9

Effect of Electronegativity on Bond Length (heteronuclear molecules)

Answer 9

In heteronuclear molecules (molecules made of different atoms), the bond length decreases as the difference in electronegativity increases.

Question 10

What is chemical bonding?

Answer 10

Chemical bonding is the process by which atoms combine to form molecules or compounds by gaining, losing, or sharing electrons.

Question 11

What is an ionic bond?

Answer 11

An ionic bond is formed when one atom transfers an electron to another atom, resulting in the formation of positively and negatively charged ions.

Question 12

Give an example of an ionic bond.

Answer 12

The bond between sodium (Na) and chlorine (Cl) in sodium chloride (NaCl) is an example of an ionic bond.

Question 13

What are the types of covalent bonds?

Answer 13

Covalent bonds can be:
Single bond (sharing one pair of electrons)
Double bond (sharing two pairs of electrons)
Triple bond (sharing three pairs of electrons)

Question 13

What is a coordinate covalent bond?

Answer 13

A coordinate covalent bond occurs when one atom donates both electrons to form a bond, as in the case of NH4+.

Question 13

What is a covalent bond?

Answer 13

A covalent bond is formed when two atoms share a pair of electrons to achieve a stable electronic configuration.

Question 14

What is a metallic bond?

Answer 14

A metallic bond is formed by the attraction between the positive metal ions and the sea of delocalized electrons.

Question 14

Give an example of a covalent bond.

Answer 14

The bond between two hydrogen atoms (H2) is an example of a covalent bond.

Question 15

What is electronegativity?

Answer 15

Electronegativity is the tendency of an atom to attract shared electrons towards itself in a chemical bond.

Question 16

What is the difference between polar and non-polar covalent bonds?

Answer 16

• Polar bond: Unequal sharing of electrons between atoms of different electronegativities (e.g., HCl).
• Non-polar bond: Equal sharing of electrons between atoms of similar electronegativity (e.g., Cl2).

Question 17

What is bond energy?

Answer 17

Bond energy is the amount of energy required to break one mole of bonds in a chemical compound.

Question 18

What is bond length?

Answer 18

Bond length is the distance between the nuclei of two bonded atoms.

Question 19

What is a dipole moment?

Answer 19

Dipole moment is a measure of the polarity of a bond and is defined as the product of the charge and the distance between the charges.

Question 20

What does VSEPR theory state?

Answer 20

The Valence Shell Electron Pair Repulsion (VSEPR) theory states that electron pairs around a central atom arrange themselves as far apart as possible to minimize repulsion.

Question 21

What are the types of hybridization?

Answer 21

Types of hybridization include:
- sp (linear)
- sp2 (trigonal planar)
- sp3 (tetrahedral)

Question 21

What is hybridization?

Answer 21

Hybridization is the mixing of atomic orbitals to form new hybrid orbitals that are degenerate in energy and shape, used to describe the bonding in molecules.

Question 22

What is the molecular orbital theory?

Answer 22

The molecular orbital theory explains bonding by the combination of atomic orbitals to form molecular orbitals, which can be bonding or antibonding.

Question 23

What is bond order?

Answer 23

Bond order is the number of chemical bonds between a pair of atoms. In molecular orbital theory, it is calculated as
B.O= (number of bonding electrons - number of antibonding electrons)/2.

Question 24

What is the difference between sigma and pi bonds?

Answer 24

• Sigma bond: A bond formed by the head-on overlap of orbitals (stronger).
• Pi bond: A bond formed by the side-by-side overlap of orbitals (weaker).

Question 25

What is bond angle?

Answer 25

Bond angle is the angle formed between three atoms across at least two bonds.

Question 26

How is a sigma bond formed?

Answer 26

A sigma bond is formed by the direct, head-on overlap of orbitals along the bond axis, creating the strongest type of covalent bond.

Question 27

What is bond enthalpy?

Answer 27

Bond enthalpy is the energy change that occurs when one mole of bonds of a particular type is broken in the gaseous state.

Question 28

How is a pi bond formed?

Answer 28

A pi bond is formed by the sideways overlap of two unhybridized p orbitals, typically seen in double and triple bonds, adding to the sigma bond.

Question 29

What is the bond angle and molecular shape of a bent molecule?

Answer 29

In a bent molecule, the bond angle is typically less than 120° or 109.5° depending on the hybridization (e.g., H2O).

Question 30

What is the bond angle and molecular shape of a trigonal planar molecule?

Answer 30

In a trigonal planar molecule, the bond angle is 120°, and the molecular shape involves three bonds arranged in a flat triangle around a central atom (e.g., BF3).

Question 31

How are hybrid orbitals formed?

Answer 31

Hybrid orbitals are formed when atomic orbitals of similar energies mix to form new orbitals. The number of hybrid orbitals equals the number of atomic orbitals mixed.

Question 32

What is the bond angle and molecular shape of a linear molecule?

Answer 32

In a linear molecule, the bond angle is 180°, and the molecular shape involves two bonds arranged in a straight line around a central atom (e.g., CO2).

Question 33

What is the bond angle and molecular shape of a tetrahedral molecule?

Answer 33

In a tetrahedral molecule, the bond angle is 109.5°, and the molecular shape involves four bonds arranged symmetrically around a central atom (e.g., CH4).

Question 34

What is the difference between polar and non-polar covalent bonds?

Answer 34

• Polar covalent bond: Electrons are shared unequally between atoms (e.g., HCl).
• Non-polar covalent bond: Electrons are shared equally (e.g., Cl₂).

Question 35

What is a dipole moment?

Answer 35

A dipole moment occurs in a polar covalent bond, where one atom has a partial negative charge, and the other has a partial positive charge due to unequal electron sharing.

Question 36

What is the octet rule?

Answer 36

The octet rule states that atoms tend to form bonds to have eight electrons in their valence shell, mimicking the electron configuration of a noble gas.

Question 37

What is bond dissociation energy?

Answer 37

Bond dissociation energy is the energy required to break a specific bond in one mole of gaseous molecules.

Question 37

Define lattice energy.

Answer 37

Lattice energy is the energy released when one mole of an ionic solid forms from its gaseous ions.