Covalent Molecular Substances: Polarity and Structure

Flashcards covering the identification of polar vs. non-polar bonds, molecular symmetry, and the criteria for determining the overall polarity of covalent molecular substances based on lecture notes.

Covalent Molecular Substances

The specific type of substances explored in this lesson, particularly concerning their polarity.

Polar Bonds

Bonds where there is an unequal sharing of electrons; examples from the transcript include $O-H$, $N-H$, $C-H$, and $C-F$.

Non-polar Bonds

Bonds where electrons are shared equally between atoms; examples from the transcript include $H-H$ and $N-N$.

Electronegativity Trend

On the periodic table, this property increases as you move up a group and across a period from left to right.

Symmetrical Molecular Shapes

Shapes that can lead to a non-polar molecule if outer atoms are identical; includes Linear, Triangular planar, and Tetrahedral.

Unsymmetrical Molecular Shapes

Shapes that are inherently non-symmetrical, leading to polarity if polar bonds are present; includes Bent and Trigonal Pyramidal.

Molecular Polarity Factors

Determination based on whether the molecule contains polar bonds and whether the shape of the molecule is symmetrical.

$CO_2$ Polarity

A Non-Polar molecule with a Linear shape because it has no non-bonding electron pairs on the central atom and the outer atoms are not different.

$HCN$ Polarity

A Polar molecule with a Linear shape because the outer atoms are different from each other.

$CH_2O$ Polarity

A Polar molecule with a Trigonal Planar shape because the outer atoms are different from each other.

$PCl_3$ Polarity

A Polar molecule with a Trigonal Pyramidal shape because there are non-bonding electron pairs around the central atom.

$H_2O$ Polarity

A Polar molecule with a Bent shape because there are non-bonding electron pairs around the central atom.

$CS_2$ Polarity

A Non-Polar molecule with a Linear shape because it has no non-bonding electron pairs and the outer atoms are the same.

$HOCl$ Polarity

A Polar molecule with a Bent shape because it has non-bonding electron pairs around the central atom.

$SiH_4$ Polarity

A Non-Polar molecule with a Tetrahedral shape because it has no non-bonding electron pairs and all outer atoms are the same.

$CH_3F$ Polarity

A Polar molecule with a Tetrahedral shape because the outer atoms are different from each other.

$BF_3$ Polarity

A Non-Polar molecule with a Trigonal Planar shape because it has no non-bonding electron pairs and all outer atoms are the same.