What Are Covalent Bonds | Properties of Matter | Chemistry | FuseSchool

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17 Apr 201605:52

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TLDRThe video script offers an insightful exploration into covalent bonding, a fundamental concept in chemistry. It explains how covalent bonds are formed through the sharing of electrons between atoms, particularly when non-metals combine. The script highlights the distinction between covalent and ionic bonds, noting that covalent bonds are directional and strong due to the close proximity of atoms resulting from orbital overlap. It also differentiates between small covalent molecules, which have low melting and boiling points and are volatile and non-conductive, and giant covalent compounds like diamond, which have high melting and boiling points due to the rigidity of their large structures. The video further discusses the role of carbon and silicon in forming giant covalent compounds and touches on the concept of allotropes, different structural forms of the same element. The challenge presented at the end invites viewers to identify covalent compounds based on their physical properties and positions on the periodic table, reinforcing the educational value of the content.

Takeaways

🔬 Covalent bonds are formed when similar atoms, such as non-metals, share electrons rather than swapping them, which is characteristic of ionic bonding.
🌟 Non-metals, typically found on the right side and upper part of the periodic table, have a tendency to share electrons due to their partially filled valence shells.
💧 Common non-metals that participate in covalent bonding include carbon, nitrogen, oxygen, and the halogens.
🚫 Non-metals generally do not lose electrons due to the energetically unfavorable nature of such a process; instead, they form covalent bonds by overlapping orbitals.
🔗 A covalent bond is represented by a straight line in chemical formulas, indicating the sharing of a pair of electrons between two atoms.
📊 Covalent bonds can also be depicted using dot and cross diagrams, which illustrate the valence electrons involved in the bonding process.
🧭 Covalent bonds are directional, meaning the atoms are held in a fixed position relative to each other, unlike ionic bonds which are formed through electrostatic attraction.
💪 The close proximity of atoms in covalent bonds due to orbital overlap results in strong bonds.
🧊 Small covalent molecules have low melting and boiling points and are volatile, while giant covalent compounds like diamond have high melting and boiling points.
🌿 Carbon and silicon are notable for forming giant covalent structures, with carbon being the basis of organic chemistry and silicon contributing to the chemistry of rocks.
⛄️ Diamond is an example of a giant covalent structure where each carbon atom forms four bonds, creating a rigid lattice that requires significant energy to break.
🔍 Allotropes of non-metals, which are different structural forms of the same element, also bond covalently, as explained in the video on allotropes of non-metals.

Q & A

What are covalent bonds?
-Covalent bonds are formed when similar atoms, such as non-metals, share electrons in their outer shells. This electron sharing occurs through the overlapping of orbitals, creating a bonding orbital that contains two electrons.
Why do non-metals typically form covalent bonds?
-Non-metals, which are found on the right-hand side and upper part of the periodic table, have partially filled valence shells and a strong attraction for a few additional electrons. It is energetically unfavorable for them to lose electrons, so they share electrons by overlapping orbitals, forming covalent bonds.
How are covalent bonds represented in a compound formula?
-Covalent bonds are represented with a straight line in a compound formula, indicating the sharing of electrons between atoms.
What is a dot and cross diagram, and how does it relate to covalent bonds?
-A dot and cross diagram is a visual representation that shows only the valence electrons involved in covalent bonding. It helps to illustrate the sharing of electrons between atoms in a molecule.
Why are covalent bonds considered directional?
-Covalent bonds are directional because the overlap of orbitals that create these bonds occurs in a specific orientation, similar to how hands hold each other in a fixed position.
How do the properties of covalent compounds differ from ionic compounds?
-Covalent compounds have low melting and boiling points, are volatile, and do not conduct electricity. They have weaker intermolecular forces compared to the electrostatic attraction in ionic compounds. Covalent bonds are also stronger because the atoms involved are very close due to the overlap of orbitals.
What are the two types of covalent structures mentioned in the script?
-The two types of covalent structures are small molecules, such as water, and giant compounds, like diamond. Small molecules have one or two bonds, while giant compounds form extensive lattices or chains with many linked atoms.
Why do giant covalent compounds have high melting and boiling points?
-Giant covalent compounds have high melting and boiling points because breaking them down requires the disruption of strong covalent bonds rather than just overcoming weaker intermolecular forces.
What is an allotrope, and how does it relate to covalent bonding?
-An allotrope is a different structural form of the same element. Non-metal allotropes bond covalently, forming different structures while still sharing electrons, as seen in the example of diamond, which is a form of carbon where each atom forms four covalent bonds.
Which elements are mentioned in the script as common non-metals?
-The common non-metals mentioned in the script are carbon, nitrogen, oxygen, and the halides.
How does the structure of a diamond relate to its properties?
-Diamond's structure, which consists of carbon atoms forming four covalent bonds with each other, results in a very large and rigid lattice. This gives diamond its exceptional hardness, high melting and boiling points, and insulating properties.
What is the significance of the challenge presented at the end of the script?
-The challenge is designed to test the viewer's understanding of covalent compounds and their properties. It asks the viewer to identify which compounds are covalent based on their physical properties and the elements' positions on the periodic table.

Outlines

00:00

🔬 Understanding Covalent Bonds

This paragraph introduces covalent bonds, explaining how they are formed between similar atoms, typically non-metals, by sharing electrons. It highlights that non-metals, found on the right and upper part of the periodic table, have partially filled electron shells and are reluctant to lose electrons, thus preferring to share. The paragraph also describes the representation of covalent bonds in chemical formulas and dot and cross diagrams, and notes their directional nature. It distinguishes covalent from ionic bonds and outlines the properties of covalent compounds, such as being non-polar, having low melting and boiling points, and not conducting electricity. It also touches on the structure of giant covalent compounds like diamond and the concept of allotropes.

05:01

🌐 Properties and Examples of Covalent Compounds

The second paragraph delves into the properties of covalent compounds, emphasizing their small molecular structures and the formation of covalent bonds between hydrogen and carbon in organic molecules. It mentions specific examples such as carbon dioxide, carbon monoxide, and methanol, and also discusses larger structures like fullerenes (e.g., C70) and silicon dioxide. The paragraph concludes by reinforcing the viewer's ability to identify covalent compounds and recognize their distinct properties.

Mindmap

Keywords

💡Covalent Bonds

Covalent bonds are a type of chemical bond formed by the sharing of electron pairs between atoms. They are a central theme of the video, which explains how these bonds are made and how they contribute to the structure and properties of different compounds. In the context of the video, covalent bonds are formed when non-metal atoms share electrons, as opposed to ionic bonding where electrons are transferred between atoms with very different reactivities.

💡Valence Shell

The valence shell, also known as the outer electron shell, is the outermost shell of an atom where electrons are involved in chemical bonding. The video discusses how atoms with partially filled valence shells bond by sharing or swapping electrons, which is key to understanding covalent bonding. Non-metals, which are typically found on the right side and upper part of the periodic table, have valence shells that are half or more filled with electrons.

💡Non-Metals

Non-metals are elements that are not metals and are typically found on the right-hand side and upper part of the periodic table. They are important in the context of covalent bonding because they tend to share electrons rather than transfer them, leading to the formation of covalent bonds. Examples given in the video include carbon, nitrogen, oxygen, and the halogens.

💡Ionic Bonding

Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions. It is mentioned in the video to contrast with covalent bonding. Ionic bonds typically occur when very different atoms, such as metals and non-metals, react with each other, resulting in the transfer of electrons from one atom to another.

💡Overlapping Orbitals

Overlapping orbitals is the process where the electron orbitals of two atoms overlap to allow for the sharing of electrons, leading to the formation of a covalent bond. The video explains that non-metals share electrons by overlapping orbitals, which creates a bonding orbital that contains two electrons, exemplifying the formation of a covalent bond.

💡Bonding Orbital

A bonding orbital is the space where two atoms share a pair of electrons, resulting in a covalent bond. The video describes how the overlap of orbitals creates a bonding orbital, which is a key mechanism in covalent bonding. This is significant because it allows atoms to be very close to each other, contributing to the strength of the covalent bond.

💡Dot and Cross Diagram

A dot and cross diagram is a visual representation used to depict the electron structure of atoms, particularly focusing on the valence electrons involved in bonding. The video mentions these diagrams as a way to represent covalent bonds and to show only the valence electrons, which is helpful for understanding how atoms share electrons to form these bonds.

💡Directionality

Directionality in covalent bonding refers to the fixed position of the bonds, which is likened to holding hands in the video. This is in contrast to ionic bonds, which are formed through electrostatic attraction between charged ions and do not have a fixed direction. The directionality of covalent bonds is important for the three-dimensional structure of molecules.

💡Giant Covalent Compounds

Giant covalent compounds are large structures formed by covalent bonding, where atoms are linked together in a lattice or chain. The video discusses how carbon and silicon, for example, can form giant covalent compounds like diamond, where each carbon atom forms four covalent bonds, creating a rigid and strong structure with very high melting and boiling points.

💡Polarization

Polarization in the context of covalent bonds refers to the uneven distribution of electron density between atoms in a bond. The video notes that in covalent bonds formed between similar atoms, such as non-metals, the electrons are evenly shared, resulting in non-polar bonds. This lack of polarization contributes to the weak intermolecular forces and low melting and boiling points of small covalent molecules.

💡Allotropes

Allotropes are different structural forms of the same element in the same physical state. The video mentions that non-metals can form allotropes that are bonded covalently. For example, different forms of carbon, such as diamond and graphite, are allotropes that exhibit different properties due to the different ways their atoms are bonded together.

Highlights

Covalent bonds are formed by the sharing of electrons between atoms, particularly when similar non-metal atoms react with each other.

Non-metals, typically found on the right side and upper part of the periodic table, share electrons by overlapping orbitals to form covalent bonds.

Common non-metals that form covalent bonds include carbon, nitrogen, oxygen, and the halogens.

Covalent bonds can be represented in chemical formulas with straight lines or as dot and cross diagrams, which only show valence electrons.

Covalent bonds are directional and fixed in position, unlike ionic bonds which are formed through electrostatic attraction between charged ions.

The close proximity of atoms in covalent bonds due to orbital overlap results in strong bonds.

Covalent compounds can be small molecules, like water, or giant compounds, like diamond, depending on the bonding structure.

In small covalent molecules, the even sharing of electrons results in non-polarized bonds and weak intermolecular forces.

Compounds made from small covalent molecules have low melting and boiling points, are volatile, and do not conduct electricity.

Giant covalent compounds, such as diamond, have very high melting and boiling points because breaking the covalent bonds requires more energy than overcoming intermolecular forces.

Carbon and silicon, which tend to form giant covalent compounds, create large lattices or chains by forming four bonds with other atoms.

Diamond is an example of a giant covalent compound, where each carbon atom forms four covalent bonds, resulting in a rigid and strong structure.

Allotropes of non-metals, which are different structural forms of the same element, bond covalently.

Covalent compounds can be identified by considering their physical properties and the elements' positions on the periodic table.

Examples of covalent compounds include carbon dioxide, carbon monoxide, methanol, C70 fullerene, and silicon dioxide.

Silicon dioxide forms a giant covalent structure similar to diamond but with oxygen atoms bridging between silicon atoms.

Understanding covalent bonding is crucial for recognizing the properties and structures of organic compounds and the chemistry of rocks.

Transcripts

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Takeaways

Q & A