Reading Mode: 2.2 Chemical Bonds and Molecules

What are polar covalent bonds?

Covalent bonds where electrons are shared unequally between atoms, resulting in a dipole moment.

Define covalent bond.

A chemical bond formed by the sharing of electron pairs between atoms.

What does it mean if a bond is nonpolar?

Electrons are shared equally between the two atoms, resulting in no dipole moment. (usually the same elements with “C-H” being the only exception)

What is the significance of the electronegativity difference in polar covalent bonds?

It determines the polarity of the bond; a greater difference results in a more polar bond.

Identify a characteristic of polar molecules.

They have a permanent dipole moment due to unequal sharing of electrons.

What is the role of hydrogen bonds in molecules?

Weak attractions that occur between polar molecules, enhancing properties like boiling point.

Give an example of a polar molecule.

Water (H2O) is a common example due to its bent shape and uneven electron distribution.

What type of bond is formed in ionic compounds?

Ionic bonds, formed through the transfer of electrons from one atom to another.

What is the effect of dipole-dipole interactions?

They influence the physical properties of polar molecules, such as boiling point.

Describe a characteristic of nonpolar molecules.

They do not have distinct positive or negative ends due to equal electron sharing.

In which type of bond do atoms gain or lose electrons?

In ionic bonds, atoms transfer electrons to achieve full valence shells.

What determines the polarity of a covalent bond?

The difference in electronegativity between the bonded atoms.

How do covalent bonds differ from ionic bonds?

Covalent bonds involve sharing electrons, while ionic bonds involve electron transfer.

Why are hydrocarbons generally nonpolar?

They consist mainly of carbon and hydrogen, which have similar electronegativities.

What is a dipole moment?

A measure of the polarity of a bond or molecule, indicating separation of charge.

Define electronegativity.

The tendency of an atom to attract electrons in a chemical bond.

What is the relationship between molecular shape and polarity?

Molecular shape affects the distribution of charges and thus the overall polarity of the molecule.

Examples of polar covalent bonds include:

Bonds between oxygen and hydrogen or nitrogen and hydrogen.

What kind of forces hold molecules together in covalent bonding?

Shared electron pairs between atoms create attractions that hold molecules together.

What is the outcome of a hydrogen bond?

It can significantly affect molecular properties like boiling points and solubility.

How do nonpolar molecules interact with polar solvents?

They tend to be insoluble in polar solvents due to lack of attraction.

What is a coordinated covalent bond?

A bond where one atom donates both electrons in a shared pair.

How can you identify a polar molecule in a compound?

Look for an asymmetrical molecular shape and the presence of polar bonds.

What is a common molecule that exhibits hydrogen bonding?

Ammonia (NH3) exhibits hydrogen bonding due to the presence of nitrogen.

State the principle behind molecular orbital theory.

Molecular orbital theory describes how atomic orbitals combine to form molecular orbitals.

What is the difference between strong and weak acids based on bonding?

Strong acids ionize completely in solution, whereas weak acids do not.

Which of the following best describes how a hyrogen bond forms?

A partially positive hydrogen atom is attracted to a partially negative atom in two polar molecules are attracted by electrostatic interactions.

An electrically charged atom

ion

Electronegativity is the ability of an atom to

attract electrons

What characteristic does this belong to? “The shared electrons are closer to one nucleus, than to the other.

polar covalent bond

Within an atom’s structure, electrons can be found:

in cloud like orbitals.

What characteristic does this belong to? “The two atoms have similiar electronegativity values

nonpolar covalent bond

electronegativity is the ability of an atom to

attract electrons

What accounts for 63% of the atoms in the body?

Hydrogen

When an atom shared two pairs of electrons

A double bond occurs

Structural formulas depict molecules with what type of bonds?

Covalent

Describe a contemporary model of electron movement within atoms

Electrons move in orbitals although their exact location cannot be precisely predicted in these orbitals

Elements that differ in the number of neutrons it contains

Isotopes

What determines whether a covalent bond is polar or nonpolar?

Electronegativity of the atoms involved in the bond

what types of chemical bonds dissolve in water

Ionic bonds and polar covalent bonds

Electronegativity differences between atoms dictate the polarity of molecules by

Influencing whether covalent bonds are polar or nonpolar