4.7.2 - Covalent Bond
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Introduction to Covalent Bonds
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Today, we're going to discuss covalent bonds. What do you think happens when two non-metal atoms approach each other?
Maybe they stick together?
Do they transfer electrons like in ionic bonds?
Great questions! Instead of transferring electrons, they share electrons. This sharing helps both of them fill their outer shells, following something we call the octet rule.
So, both atoms benefit from that?
Exactly! For instance, in a hydrogen molecule, two hydrogen atoms share one pair of electrons to form H₂.
That's interesting! But how does that help them become stable?
Good question! By sharing, they effectively have two electrons each in their outer shell, thus achieving a stable electron configuration.
To recap, a covalent bond is formed by the sharing of electrons between atoms, particularly non-metals. This sharing leads both atoms towards stability.
Examples of Covalent Bonds
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Now, let’s look at some examples of covalent compounds. Can anyone name a simple molecule formed by covalent bonding?
What about water? Is that a covalent bond?
Yes! In water (H₂O), we have two hydrogen atoms bonding with one oxygen atom. They share electrons, but how many shared pairs does each bond involve?
I think two hydrogen atoms each share one electron with the oxygen, right?
Correct! Also, oxygen shares two pairs of electrons in total with both hydrogen atoms. What about oxygen itself, any thoughts?
Oxygen (O₂) has to share between the two oxygen atoms as well?
Exactly! In O₂, the two oxygen atoms share two pairs of electrons, creating a double bond. This is why it’s important for life!
So, to summarize, covalent bonding is vital in compounds like water and oxygen, showcasing how shared electrons help form stable molecules.
Properties of Covalent Compounds
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Let's discuss the properties of covalent compounds. How do you think they differ from ionic compounds?
Covalent compounds might be softer than ionic ones?
And they probably have lower melting points too?
Exactly! Covalent compounds usually exist as gases or liquids and have low melting points compared to ionic compounds, which are generally solid with high melting points. Why do you think that is?
I guess it’s because they don't have strong attractions like ionic compounds do?
Right! Covalent bonds are weaker, leading to different physical properties. In summary, covalent compounds often have lower melting and boiling points and are usually poor conductors of electricity, unlike ionic compounds.
Introduction & Overview
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Quick Overview
Standard
This section explains covalent bonds, emphasizing that these bonds involve the sharing of electrons between non-metal atoms. It highlights the significance of covalent bonding in achieving stable electron configurations and provides examples such as H₂, O₂, and H₂O.
Detailed
Covalent Bond
Covalent bonds are a fundamental type of chemical bonding characterized by the sharing of electron pairs between non-metal atoms. This sharing enables each atom to attain a full valence shell, thereby achieving a more stable electronic configuration similar to that of noble gases. The section focuses on the mechanics of covalent bonding, illustrating how shared electrons contribute to the octet rule, which states that atoms seek to have eight electrons in their outer shell.
Key Points:
- Formation: Covalent bonds arise when non-metal atoms share pairs of electrons. For example, in a hydrogen molecule (H₂), two hydrogen atoms share a pair of electrons, forming a stable bond.
- Examples: Covalent compounds include diatomic molecules like oxygen (O₂) where two oxygen atoms share two pairs of electrons, and water (H₂O) where two hydrogen atoms share electrons with one oxygen atom.
- Significance: Understanding covalent bonds is essential for comprehending how molecules are formed and how they interact in chemical reactions. This knowledge also lays the foundation for more complex topics in chemistry.
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Definition of Covalent Bond
Chapter 1 of 2
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Chapter Content
● Formed by the sharing of electrons
● Between non-metal atoms
● Shared electrons contribute to both atoms’ octets
Detailed Explanation
A covalent bond occurs when two non-metal atoms share electrons. Unlike ionic bonds, where electrons are transferred from one atom to another, in covalent bonding, both atoms hold onto the electrons. This sharing of electrons allows each atom to complete its outer shell, fulfilling the octet rule, which states that atoms tend to have eight electrons in their outermost shell for stability.
Examples & Analogies
Imagine two friends sharing a pizza. Each person takes slices to feel full and satisfied. In a covalent bond, the atoms are like friends sharing electrons (pizza slices) to feel 'full' and stable by achieving a complete outer shell.
Examples of Covalent Bonds
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Chapter Content
Examples:
● H₂ (H–H)
● O₂ (O=O)
● H₂O (H–O–H)
Detailed Explanation
Covalent bonds can be observed in several common molecules. For instance, in hydrogen gas (H₂), two hydrogen atoms share one pair of electrons. In oxygen gas (O₂), two oxygen atoms share two pairs, forming a double bond. Water (H₂O) demonstrates covalent bonding as oxygen shares electrons with two hydrogen atoms. These examples show how atoms combine through the sharing of electrons to form stable molecules.
Examples & Analogies
Think of a partnership in a project where two people (atoms) come together, each bringing their expertise (electrons). In H₂, only one expert is needed (one bond), while in O₂, both bring additional skills (two bonds) to enhance their project. In water (H₂O), one expert leads (oxygen) while two additional members (hydrogens) contribute equally to complete the project successfully.
Key Concepts
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Covalent Bond: A bond formed by the sharing of electrons between non-metal atoms.
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Octet Rule: Atoms share or transfer electrons to complete their outer electron shell, typically achieving eight electrons.
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Examples: Compounds like H₂, O₂, and H₂O demonstrate covalent bonding.
Examples & Applications
H₂ (Hydrogen) exhibits a single covalent bond through the sharing of one pair of electrons.
O₂ (Oxygen) features a double bond represented by the sharing of two pairs of electrons.
H₂O (Water) is a compound where oxygen shares electrons with two hydrogen atoms, creating two single covalent bonds.
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Rhymes
In pairs they share, electrons two, Covalent bonds connect me and you.
Stories
Once in Atom Land, two hydrogen atoms met an oxygen. They wanted to be friends, so they shared their toys (electrons) and formed a water molecule, living happily ever after!
Memory Tools
To remember covalent bonds, think of 'SHARE': Sharing Helps Atoms Reach Electrons.
Acronyms
COVALENT
'C' for Connect
'O' for Oxygen
'V' for valence
'A' for atoms
'L' for lose not
'E' for electrons
'N' for no transfer
'T' for together.
Flash Cards
Glossary
- Covalent Bond
A type of chemical bond formed by the sharing of electron pairs between atoms.
- NonMetal
Elements that are generally poor conductors of heat and electricity and which usually form covalent bonds.
- Octet Rule
A chemical rule stating that atoms tend to bond in such a way that they each have eight electrons in their valence shell.
- Molecule
A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound.
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