Predicting bond type (electronegativity) | Types of chemical bonds | AP Chemistry | Khan Academy

Summary

This video script discusses the spectrum of chemical bonding, emphasizing that bonds are not strictly ionic, covalent, or metallic but can vary in nature. It explains how electronegativity differences influence bond polarity, using the example of a polar covalent bond between oxygen and hydrogen. The script also touches on metallic bonds, which form when two low electronegativity elements share electrons in a communal pool, leading to properties like conductivity.

Takeaways

• 🔬 Bonding between atoms can be categorized as metallic, covalent, or ionic, depending on the elements involved.
• 🌟 The nature of bonds is a spectrum, with polar covalent bonds exhibiting characteristics between nonpolar covalent and ionic bonds.
• 📊 Electronegativity is a key factor in determining the type of bond formed, representing an atom's ability to attract electrons.
• 📉 A low difference in electronegativity between atoms leads to nonpolar covalent or metallic bonds.
• 📈 A high difference in electronegativity results in polar covalent or ionic bonds, with the more electronegative atom attracting the electrons more.
• 🧲 Electronegativity increases from the bottom left to the top right on the periodic table.
• 🔋 Metallic bonds typically form between elements with similar and relatively low electronegativities, facilitating the sharing of electrons.
• 💧 In a polar covalent bond, such as between oxygen and hydrogen, there is an unequal sharing of electrons, leading to partial charges on each atom.
• 🌐 The Pauling scale is used to measure electronegativity, with oxygen being one of the most electronegative elements.
• 🔄 Electrons in a polar covalent bond spend more time around the more electronegative atom, creating a dipole.

Q & A

What are the three main types of bonds that can form between atoms?

The three main types of bonds are metallic bonds, covalent bonds, and ionic bonds. Metallic bonds typically form between two metals, covalent bonds form between two nonmetals, and ionic bonds form between a metal and a nonmetal.

What is the significance of electronegativity in determining the type of bond formed?

Electronegativity is a measure of an atom's ability to attract electrons in a bond. It plays a crucial role in determining the polarity of a bond. A large difference in electronegativity between two atoms typically results in an ionic bond, while a small difference leads to a covalent bond.

How does the concept of a bonding spectrum relate to electronegativity?

The bonding spectrum is a way to visualize the gradual transition from nonpolar covalent bonds to polar covalent bonds and eventually to ionic bonds based on the difference in electronegativity between the bonded atoms.

What is a polar covalent bond and how does it differ from a nonpolar covalent bond?

A polar covalent bond is a type of covalent bond where the electrons are shared unequally between the atoms due to a difference in electronegativity, resulting in a partial positive charge on one atom and a partial negative charge on the other. A nonpolar covalent bond occurs when the electrons are shared equally because the electronegativity of the atoms is similar.

What is the Pauling scale and how is it used to measure electronegativity?

The Pauling scale is a scale used to measure electronegativity, named after the chemist Linus Pauling. It assigns a number to each element that represents its ability to attract electrons in a chemical bond.

How does the electronegativity of oxygen compare to that of hydrogen?

Oxygen is more electronegative than hydrogen, with an electronegativity of 3.44 compared to hydrogen's 2.20 on the Pauling scale. This difference makes the bond between oxygen and hydrogen a polar covalent bond.

What is the general trend of electronegativity on the periodic table?

Electronegativity generally increases from the bottom left to the top right of the periodic table. Elements at the top right are more electronegative and tend to attract electrons more strongly.

What is the role of electronegativity in the formation of metallic bonds?

In metallic bonds, the atoms involved typically have similar and relatively low electronegativities, which makes them more willing to share their valence electrons in a communal pool, leading to properties like electrical conductivity.

How does the difference in electronegativity between two atoms affect the bond's polarity?

A greater difference in electronegativity between two atoms results in a more polar bond, where the electrons are more attracted to one atom, creating a partial negative charge on that atom and a partial positive charge on the other. Conversely, a smaller difference results in a less polar or nonpolar bond.

Can you provide an example of a bond that is intermediate between covalent and ionic?

Yes, a bond between oxygen and hydrogen is an example of an intermediate bond. Although both are nonmetals and would typically form a covalent bond, the significant difference in their electronegativities (oxygen being much more electronegative) results in a polar covalent bond that has characteristics of an ionic bond.

What property of metallic bonds allows for conductivity?

Metallic bonds involve a shared pool of valence electrons that are free to move throughout the metal lattice. This 'sea' of delocalized electrons is what allows metals to conduct electricity.