L2: Understanding Atomic Structure and Bonding

The ________in an atom don't stay still; they exist in orbitals where there's a 90% probability of finding them. It's like trying to track the wings of a hummingbird!

• Proton

• Neuron

• Electron

• Isotope

Answer explanation

Explanation: Electrons in an atom are not stationary; they occupy orbitals where there's a high probability (90%) of locating them, similar to the unpredictable movement of a hummingbird's wings.

1. Fun Fact: This is why atoms have unique shapes and properties based on how their orbitals overlap.

Carbon can "shape-shift" its orbitals to form single, double, or triple bonds. This is called ________ and is why carbon forms such a wide variety of molecules.

• excitation

• hybridization

• degenerate

• trivalent

Answer explanation

Explanation: Carbon's ability to hybridize its orbitals allows it to form single, double, or triple bonds, enabling the creation of a diverse range of molecules. This flexibility is key to carbon's role in organic chemistry.

1. Fun Fact: Without this flexibility, there would be no diamonds, graphite, or even organic life!

When atoms bond, it's like waves colliding. If they sync up, they bond; if not, they repel. _______interference strengthens the bond, while destructive interference prevents bonding.

• None

• Destructive

• Constructive

• Node

Answer explanation

Explanation: Atoms bond through wave interactions. When their wave patterns sync (constructive interference), they bond; if they don't sync (destructive interference), they repel. Thus, constructive interference strengthens the bond.

3. Fun Fact: This principle is similar to how noise-canceling headphones block unwanted sound waves!

Electrons can occupy molecular orbitals that span across multiple atoms, creating______. This concept helps explain why some materials are stronger or more flexible.

• bonds

• electricity

• sparks

• wave

Answer explanation

Explanation: Electrons in molecular orbitals allow for bonding across multiple atoms, which contributes to the strength and flexibility of materials. This explains variations in material properties based on their molecular structure.

5. Fun Fact: Molecular orbitals explain why metals conduct electricity and why rubber is stretchy.

When atoms bond, they create sigma (σ) and pi (π) bonds, each with distinct structures. ______ bonds are stronger and form the backbone of molecules, while ______bonds add flexibility.

• Pi, sigma

• Sigma, sigma

• Sigma, pi

• Pi, pi

Answer explanation

Explanation: Sigma (σ) bonds are stronger and form the main structure of molecules, while pi (π) bonds provide additional flexibility. This distinction highlights the importance of sigma bonds in molecular stability.

5. Fun Fact: This is why double-bonded molecules like ethene are more reactive than single-bonded ones like methane.

Methane (CH₄) has ______hybridized carbon, which gives it a tetrahedral shape. This symmetry makes it highly stable as a natural gas for cooking and heating.

• sp

• sp²

• sp³

• s

Answer explanation

Explanation: Methane (CH₄) has sp³ hybridization, resulting in a tetrahedral shape. This geometric symmetry contributes to its stability, making it an effective and reliable natural gas for cooking and heating.

7. Fun Fact: Natural gas in your home is mostly methane, showing hybridization in action!

Ethene (C₂H₄), used to ripen fruits, has ______ hybridized carbons, which allows for the double bond between carbons.

• sp

• sp²

• sp³

• p

Answer explanation

Explanation: Ethene (C₂H₄) has sp² hybridization, which involves one s and two p orbitals mixing to form three sp² hybrid orbitals. This configuration allows for the formation of a double bond between the two carbon atoms, essential for its role in ripening fruits.

7. Fun Fact: This double bond makes ethene highly reactive, which is why it can stimulate ripening in fruits.

Acetylene (C₂H₂), used in welding, has a triple bond between two carbons due to _______ hybridization. This bond is super strong and releases a lot of energy when broken.

• sp

• sp²

• sp³

• s

Answer explanation

Explanation: Acetylene (C₂H₂) features a triple bond between carbon atoms due to sp hybridization, making it extremely strong. This bond's strength results in significant energy release when it is broken, which is essential for welding applications.

9. Fun Fact: This high energy makes acetylene perfect for cutting through metal!

Molecules arrange themselves to minimize electron repulsion. This is why water (H₂O) has a ______shape instead of a straight line.

• tetrahedral

• trigonal planar

• bent

• linear

Answer explanation

Explanation: Molecules, like water (H₂O), adopt shapes that minimize electron repulsion. The bent shape of water results from the arrangement of its hydrogen and oxygen atoms, which helps reduce repulsive forces between the electron pairs.

• Fun Fact: The angle of water molecules (104.5°) is why ice floats—its structure traps air pockets!

Did You Know? Methane (CH₄) is _________due to sp³ hybridization and the VSEPR theory. This shape makes methane stable and non-reactive under normal conditions.

• tetrahedral

• bent

• trigonal planar

• linear

Answer explanation

Explanation: Methane's tetrahedral shape arises from sp³ hybridization, leading to a stable and non-reactive molecule under normal conditions, as predicted by VSEPR theory.

• Fun Fact: Methane’s stability is why it’s found deep underground as natural gas.