Ikatan Kimia (8) | Cara Menentukan Molekul Polar dan Non Polar | Kimia Kelas 10

Summary

In this video, Kakak explains how to differentiate between polar and nonpolar covalent molecules, focusing on the concepts of electronegativity, lone electron pairs, and molecular symmetry. Polar molecules occur when atoms share electrons unequally due to differences in electronegativity, while nonpolar molecules share electrons equally. Kakak also highlights the role of atom pairing in diatomic and polyatomic molecules, showing how the presence or absence of lone electron pairs affects polarity. Additionally, molecular symmetry is used to distinguish between polar and nonpolar molecules, with polar molecules being asymmetric and nonpolar molecules typically symmetric.

Takeaways

• 😀 A covalent bond is considered polar if the electron pair is attracted more to one atom due to differences in electronegativity.
• 😀 Polar covalent bonds create a dipole with a positive and negative charge at opposite ends of the molecule.
• 😀 A nonpolar covalent bond occurs when electrons are shared equally between two atoms with similar electronegativities.
• 😀 Example of polar bonds: H-Cl, where chlorine attracts the electrons more than hydrogen.
• 😀 Example of nonpolar bonds: O2, where both atoms have the same electronegativity, leading to an equal sharing of electrons.
• 😀 Molecules with polar covalent bonds are generally polar, but exceptions exist due to molecular symmetry.
• 😀 CO2 has polar bonds but is nonpolar overall because of its linear symmetrical shape.
• 😀 For diatomic molecules, if the atoms are different, the molecule is polar; if they are the same, the molecule is nonpolar.
• 😀 For polyatomic molecules, the central atom's lone pairs can determine if the molecule is polar (lone pairs lead to polarity).
• 😀 Symmetry in molecular shape affects polarity: asymmetric shapes tend to be polar, while symmetric shapes tend to be nonpolar.
• 😀 Examples of polar molecules: PCl3, with an asymmetric shape and lone pairs on the central atom. Examples of nonpolar molecules: CH4, with a symmetrical shape and no lone pairs.

Q & A

What is the main topic of the video?

The main topic of the video is about distinguishing between polar and nonpolar covalent molecules and understanding the differences in their properties.

What is a polar covalent bond?

A polar covalent bond occurs when electrons are shared unequally between two atoms due to a difference in their electronegativity, causing a partial positive charge on one atom and a partial negative charge on the other.

Can you give an example of a polar covalent bond?

Yes, an example of a polar covalent bond is the bond between hydrogen (H) and chlorine (Cl), where chlorine has a higher electronegativity, pulling the shared electrons towards itself.

What makes a molecule polar?

A molecule becomes polar when there is an uneven distribution of electron density, often due to a difference in electronegativity between atoms, creating partial positive and negative charges at opposite ends of the molecule.

What is a nonpolar covalent bond?

A nonpolar covalent bond occurs when two atoms share electrons equally, typically because the atoms have the same electronegativity, resulting in no partial charges in the molecule.

Can you give an example of a nonpolar covalent bond?

An example of a nonpolar covalent bond is the bond between two chlorine atoms (Cl2), where the electrons are shared equally because both atoms have the same electronegativity.

How do you distinguish between a polar and nonpolar molecule based on the number of atoms?

For molecules consisting of two atoms, if the atoms are different (like HCl), the molecule is polar. If the atoms are the same (like O2 or H2), the molecule is nonpolar.

How can we determine if a molecule with more than two atoms is polar or nonpolar?

For molecules with more than two atoms, you can check if the central atom has lone electron pairs. If the central atom has lone pairs, the molecule is usually polar. If there are no lone pairs, the molecule is nonpolar.

What is the importance of molecular shape in determining whether a molecule is polar or nonpolar?

The shape of the molecule plays a crucial role in determining its polarity. Polar molecules typically have an asymmetric shape, causing an uneven distribution of charge, while nonpolar molecules are usually symmetric, leading to an even distribution of charge.

What is the Lewis structure used for in determining the polarity of a molecule?

The Lewis structure helps in visualizing how atoms in a molecule are bonded and allows the identification of lone pairs of electrons, which can help determine if the molecule is polar or nonpolar based on its electron configuration and shape.