Electronegativity and Polarity

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Electronegativity Noun

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[eh-lek-troh-neg-uh-tiv-i-tee]

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Electronegativity

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The relative ability of an atom to attract electrons when it is participating in the formation of a chemical bond.

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Example: The more electronegative oxygen atom pulls electrons from the hydrogen atoms, causing an unequal sharing of electrons in the resulting water molecule.

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Bond Character Noun

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[bond kar-ak-ter]

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Bond Character

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The nature of a chemical bond, determined by electronegativity difference, indicating if it's ionic, polar covalent, or nonpolar covalent.

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Example: This image shows that bond character is a spectrum. A large electronegativity difference (ΔEN) creates an ionic bond (electron transfer), while a small difference creates a covalent bond (equal sharing).

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Electronegativity Difference Noun

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[eh-lek-troh-neg-uh-tiv-i-tee dif-er-uhns]

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Electronegativity Difference

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The difference in electronegativity values between two atoms, which is used to predict the character of their chemical bond.

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Example: This image shows how a large electronegativity difference between atoms (like H and Cl) causes unequal electron sharing, creating a polar bond with charged ends.

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Nonpolar Covalent Bond Noun

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[non-poh-ler koh-vey-luhnt bond]

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Nonpolar Covalent Bond

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A chemical bond where electrons are shared equally between two atoms, resulting from a very small or zero electronegativity difference.

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Example: Two identical atoms share electrons equally between them, resulting in a balanced distribution of charge and forming a nonpolar covalent bond.

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Polar Covalent Bond Noun

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[poh-ler koh-vey-luhnt bond]

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Polar Covalent Bond

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A chemical bond where electrons are shared unequally between two atoms due to a significant difference in their electronegativity values.

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Example: The oxygen atom pulls electrons more strongly than the hydrogen atoms, creating an unequal sharing. This results in a partial negative charge (δ-) on oxygen and partial positive charges (δ+) on hydrogen.

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Percent Ionic Character Noun

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[per-sent ahy-on-ik kar-ak-ter]

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Percent Ionic Character

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A measure of the degree to which a chemical bond is ionic, which increases as the electronegativity difference grows larger.

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Example: This graph shows that as the difference in electronegativity between two bonded atoms increases, the bond behaves more like an ionic bond (higher percent ionic character).

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Partial Charge Noun

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[pahr-shuhl chahrj]

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Partial Charge

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A slight positive or negative charge on an atom within a polar covalent bond that is caused by unequal electron sharing.

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Example: In a water molecule, the more electronegative oxygen atom pulls electrons from the hydrogen atoms, creating a partial negative charge on the oxygen and partial positive charges on the hydrogens.

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Dipole Noun

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[dahy-pohl]

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Dipole

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A molecule or a chemical bond that has two poles with opposite charges, created by a separation of positive and negative charge.

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Example: In a water molecule, the more electronegative oxygen atom pulls electrons away from the hydrogen atoms, creating a separation of charge called a dipole.

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Molecular Polarity Noun

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[muh-lek-yuh-ler poh-lar-i-tee]

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Molecular Polarity

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A property of a molecule describing the uneven distribution of electric charge, which determines its attraction to an electric field.

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Example: In a water molecule, the oxygen atom pulls electrons more strongly, creating a slight negative charge (δ-), while the hydrogen atoms have a slight positive charge (δ+).

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VSEPR Model Noun

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[ves-per mod-l]

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VSEPR Model

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A model stating that valence electron pairs repel each other, thereby determining the geometric shape and bond angles in a molecule.

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Example: This image uses the VSEPR model to show how molecular shape determines polarity. Water (H₂O) is bent, making it polar, while carbon dioxide (CO₂) is linear, making it nonpolar.