Chemistry Polarity Flashcards

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Questions and Answers

Is Cl2 polar or nonpolar?

nonpolar

What is the bond angle in a trigonal planar molecule?

120 degrees

What is the bond angle in a tetrahedral molecule?

109.5 degrees

What is the bond angle in a bent molecule?

104.5 degrees Signup and view all the answers

What is the bond angle in a linear molecule?

180 degrees Signup and view all the answers

Is trigonal planar polar or nonpolar?

Nonpolar when it has the same atoms on the outside, but polar when it has different outside atoms. Signup and view all the answers

Is tetrahedral polar or nonpolar?

Nonpolar when it has the same atoms on the outside. Signup and view all the answers

Bent is always polar.

True Signup and view all the answers

What is the structure and angle in a trigonal pyramidal molecule?

3 bonds, 1 lone pair, 107 degrees Signup and view all the answers

Is trigonal pyramidal polar or nonpolar?

Polar Signup and view all the answers

Do we care about polarity?

False Signup and view all the answers

What can have polarity?

Only covalent bonds can have polarity. Signup and view all the answers

What is a polar covalent bond?

A covalent bond in which electrons are not shared equally. Signup and view all the answers

What is a non-polar bond?

A covalent bond in which electrons are shared equally. Signup and view all the answers

What is electronegativity?

A measure of the ability of an atom in a chemical compound to attract electrons. Signup and view all the answers

Does electronegativity increase or decrease across a period?

Increase Signup and view all the answers

Does electronegativity increase or decrease down a group?

Decrease Signup and view all the answers

What is shielding in chemistry?

That core electrons in inner shell will block the pull of the nucleus on valence electrons. Signup and view all the answers

What does the difference in electronegativity tell us?

The difference in electronegativity tells about the bond between two atoms. Signup and view all the answers

What is a polar bond difference in electronegativity?

Partial bond with partial charges. Difference between 0.5-1.9. Signup and view all the answers

What is a non-polar bond difference in electronegativity?

No charge and the difference between 0.0-0.4. Signup and view all the answers

What is an ionic bond?

One atom pulls so hard that it rips away the electron from the other atoms creating ions only with non-metals and metals. Signup and view all the answers

What is the electronegativity difference for an ionic bond?

Bigger than 1.9. Signup and view all the answers

What is a molecule?

Two or more atoms held together by covalent bonds. Signup and view all the answers

What is an example of a molecule?

H2O Signup and view all the answers

What is a covalent bond?

Sharing of electrons. Signup and view all the answers

What is a compound?

2 or more elements chemically combined. Signup and view all the answers

What are examples of compounds?

H2O, NaCl Signup and view all the answers

What is the octet rule?

States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons. Signup and view all the answers

What is BrINClHOF?

Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, Fluorine. Signup and view all the answers

What is a Lewis Dot Structure?

Diagram of a molecule using dots to represent valence electrons. Signup and view all the answers

Study Notes

Molecular Polarity

Cl2 is a non-polar molecule due to equal electron distribution between two chlorine atoms.
Polarity in trigonal planar molecules depends on the atoms involved: non-polar if the same atoms are present, polar if different.

Molecular Geometry and Angles

Trigonal planar shape has bond angles of 120 degrees.
Tetrahedral shape features bond angles of 109.5 degrees.
Bent shape exhibits bond angles of 104.5 degrees.
Linear shape has bond angles of 180 degrees.
Trigonal pyramidal geometry consists of 3 bonds and 1 lone pair, with bond angles of 107 degrees.

Polarity Characteristics

Bent molecules are always polar.
Tetrahedral shapes remain non-polar when all peripheral atoms are identical.
Trigonal pyramidal structures are inherently polar due to uneven charge distribution.

Significance of Polarity

Polarity is a helpful concept for understanding molecular behavior, even if not of direct concern.
Only covalent bonds can exhibit polarity.

Bonding Concepts

A polar covalent bond arises when electrons are shared unequally between atoms.
A non-polar bond occurs when electrons are shared equally.
Electronegativity measures an atom's ability to attract electrons in a chemical compound.

Electronegativity Trends

Electronegativity increases across a period on the periodic table.
Electronegativity decreases down a group.

Shielding Effect

Shielding occurs when core electrons block the attractive force of the nucleus on valence electrons.

Electronegativity Differences and Bonding Types

A difference in electronegativity indicates polarity in bonds:
- Polar bonds have a difference of 0.5 to 1.9.
- Non-polar bonds feature a difference of 0.0 to 0.4.
- Ionic bonds typically arise with a difference greater than 1.9, leading to the formation of charged ions, generally between metals and non-metals.

Molecular and Compound Definitions

A molecule is defined as two or more atoms held together by covalent bonds (example: H2O).
A compound consists of two or more elements chemically combined (examples: H2O, NaCl).

Octet Rule

The octet rule states that atoms tend to lose, gain, or share electrons to achieve a full set of eight valence electrons, promoting stability.

Diatomic Molecules

BrINClHOF refers to the diatomic elements: Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine.

Lewis Dot Structure

A Lewis Dot Structure is a diagram representing a molecule using dots to indicate valence electrons, providing insight into bonding and molecular configuration.

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Description

Test your knowledge on the polarity of molecules and their shapes with these flashcards. Learn about terms like polar, nonpolar, and various molecular geometries like trigonal planar and tetrahedral. Great for chemistry students looking to reinforce their understanding of molecular structures.