Semester Review #2: Unit 4 & 5: Modern Atomic Theory & Bonding

Front

What is polarity in a molecule?

Back

Polarity refers to the distribution of electrical charge over the atoms joined by the bond. A polar molecule has a partial positive charge on one end and a partial negative charge on the other due to differences in electronegativity.

Front

Which molecule is more polar: HCl or CCl4?

Back

HCl is more polar than CCl4 because HCl has a significant difference in electronegativity between hydrogen and chlorine, while CCl4 is symmetrical and nonpolar.

Front

What does the symbol above F in a Lewis structure indicate?

Back

It indicates that electrons are more attracted to Fluorine than to Hydrogen, reflecting Fluorine's higher electronegativity.

Front

Define electronegativity.

Back

Electronegativity is a measure of the tendency of an atom to attract bonding electrons. It indicates how strongly an atom can attract electrons in a chemical bond.

Front

What type of bond has a partially positive end and a partially negative end?

Back

A polar bond has a partially positive end and a partially negative end due to unequal sharing of electrons.

Front

What is the difference between polar and nonpolar molecules?

Back

Polar molecules have an uneven distribution of charge, leading to a dipole moment, while nonpolar molecules have an even distribution of charge and do not have a dipole moment.

Front

How does the electronegativity difference affect bond type?

Back

A large electronegativity difference (typically >1.7) results in an ionic bond, while a moderate difference (0.4 to 1.7) results in a polar covalent bond, and a small difference (<0.4) results in a nonpolar covalent bond.

Front

What is a Lewis structure?

Back

A Lewis structure is a diagram that represents the valence electrons of atoms within a molecule, showing how they are arranged among the atoms.

Front

What is the significance of a dipole moment in a molecule?

Back

A dipole moment indicates the polarity of a molecule; it is a vector quantity that points from the positive to the negative charge, showing the direction of the charge separation.

Front

What is the role of valence electrons in bonding?

Back

Valence electrons are the outermost electrons of an atom and are involved in forming bonds with other atoms, determining the chemical properties of the element.