Chemical Bonding: Chemical Formulas

Question 1

What is a compound?

Answer 1

A compound is a substance that is made up of two or more different elements combined together chemically

Question 2

What is the octet rule?

Answer 2

When bonding occurs, atoms tend to reach an electron arrangement with eight electrons in the outermost energy level

Question 3

What is an ion?

Answer 3

An ion is a charged atom or group of atoms

Question 4

What is an ionic bond?

2

Answer 4

The force of attraction between oppositely charged ions in a compound

Ionic bonds are always formed by the complete transfer of electrons from one atom to another

Question 5

What is a transition metal?

Answer 5

A transition metal is one that forms at least one ion with a partially filled d sublevel.

Question 6

Define a molecule.

2

Answer 6

A molecule is a group of ants joined together

It is the smallest particle of an element or compound that can exist independently

Question 7

What is the valency of an element?

Answer 7

The valency of an element is defined as the number of atoms of hydrogen or any other monovalent element with which each atom of the element combines

Question 8

What is a sigma bond?

Answer 8

A sigma bond is formed by the head-on overlap of two orbitals

Question 9

What is a pi bond?

Answer 9

A pi bond is formed by the sideways overlap of p orbitals

Question 10

What is electronegativity?

Answer 10

Electronegativity is the relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond

Question 11

What is a polar covalent bond?

2

Answer 11

A bond in which there is unequal sharing of the pair (or pairs) of electrons

This causes one end of the bond to be slightly positive and the other end slightly negative.

Question 12

What electronegativity difference indicates ionic bonding in a compound?

Answer 12

A difference greater than 1.7

Question 13

What electronegativity difference indicates covalent bonding in a compound?

Answer 13

A difference less than or equal to 1.7

Question 14

What electronegativity difference indicates that a covalent bond is polar covalent?

Answer 14

A difference greater than 0.4 and less than 1.7

Question 15

What electronegativity difference indicates that a covalent bond is non polar?

Answer 15

A difference less than or equal to 0.4

Question 16

What is intramolecular bonding?

2

Answer 16

Bonding that takes place within a molecule, i.e. it holds the atoms together

Covalent bonding and polar covalent bonding are examples of intramolecular bonding

Question 17

What are intermolecular forces?

2

Answer 17

The forces of attraction that exist between molecules

Van der Waals forces, dipole-dipole forces and hydrogen bonding are examples of intermolecular forces

Question 18

What are Van der Waals forces?

2

Answer 18

Weak attractive forces between molecules resulting from the formation of temporary dipoles.

They are the only forces of attraction between non-polar molecules

Question 19

What are dipole-dipole forces?

Answer 19

Forces of attraction between the negative pole of one polar molecule and the positive pole of another polar molecule.

Question 20

What hydrogen bonds?

3

Answer 20

Particular types of dipole-dipole attractions between molecules in which hydrogen atoms are bonded to nitrogen, oxygen or fluorine.

The hydrogen atom carries a partial positive charge and is attracted to the electronegativity atom in another molecule

Thus, the hydrogen bond acts as a bridge between two electronegative atoms in separate molecules

Question 21

Comment on the strength of the repulsion between each possible pairs of electrons

Answer 21

Lone pair/lone pair > lone pair/bond pair > bond pair/bond pair

Question 22

What is the bond angle in a linear molecule?

Answer 22

180 degrees

Question 23

What is the bond angle in triangular planar molecules?

Answer 23

120 degrees

Question 24

What is the bond angle in tetrahedron shaped molecules?

Answer 24

109.5

Question 25

What is the bond angle in pyramidal shaped molecules?

Answer 25

170 degrees

Question 26

What is the bond angle in V-shaped molecules

Answer 26

104.5

Question 27

What is the name of the molecule with bond angle equal to 180 degrees?

Answer 27

Linear

Question 28

What is the name of the molecule with bond angle equal to 120 degrees

Answer 28

Triangular planar

Question 29

What is the name of the molecule with bond angle equal to 109.5

Answer 29

Tetrahedron

Question 30

What is the name of the molecule with bond angle equal to 107 degrees

Answer 30

Pyramidal

Question 31

What is the name of the molecule with bond angle equal to 104.5 degrees

Answer 31

V-shaped