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What happens when two non-metal atoms react together to form a covalent bond?
What happens when two non-metal atoms react together to form a covalent bond?
Chlorine atoms are stable in their isolated form.
Chlorine atoms are stable in their isolated form.
False
What is the process by which atoms achieve stable outer shells in covalent bonding?
What is the process by which atoms achieve stable outer shells in covalent bonding?
Sharing electrons
In a Lewis structure, unpaired electrons are represented by a ______.
In a Lewis structure, unpaired electrons are represented by a ______.
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Match the chemical species with their corresponding charges:
Match the chemical species with their corresponding charges:
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What is the main characteristic of covalent bonds regarding energy?
What is the main characteristic of covalent bonds regarding energy?
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The octet rule states that atoms are stable when they have eight electrons in their outer shell.
The octet rule states that atoms are stable when they have eight electrons in their outer shell.
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What is the significance of valence electrons in chemical reactions?
What is the significance of valence electrons in chemical reactions?
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What is the primary feature of delocalized electrons?
What is the primary feature of delocalized electrons?
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All resonance structures of the nitrate ion NO3- have different bond lengths.
All resonance structures of the nitrate ion NO3- have different bond lengths.
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What is the true structure of a molecule that is represented by multiple resonance structures?
What is the true structure of a molecule that is represented by multiple resonance structures?
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The scenario where there are too many valence electrons is called __________.
The scenario where there are too many valence electrons is called __________.
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Match the following exceptions to the Octet Rule with their descriptions:
Match the following exceptions to the Octet Rule with their descriptions:
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Which of the following best describes the nitrate ion?
Which of the following best describes the nitrate ion?
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Boron in BH3 has a complete octet.
Boron in BH3 has a complete octet.
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What must be minimized when determining the most likely resonance structure?
What must be minimized when determining the most likely resonance structure?
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What is the molecular shape of water (H2O)?
What is the molecular shape of water (H2O)?
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Pi bonds are stronger than sigma bonds.
Pi bonds are stronger than sigma bonds.
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What type of bond has electron density symmetrical about a line joining the nuclei?
What type of bond has electron density symmetrical about a line joining the nuclei?
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A molecule with 4 bonding pairs and 0 lone pairs has a ______ geometry.
A molecule with 4 bonding pairs and 0 lone pairs has a ______ geometry.
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Match the following molecules with their molecular shapes:
Match the following molecules with their molecular shapes:
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Which molecule is polar?
Which molecule is polar?
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All tetrahedral molecules are nonpolar.
All tetrahedral molecules are nonpolar.
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What is the molecular shape of borane (BH3)?
What is the molecular shape of borane (BH3)?
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What happens to bond strength as more electrons are shared?
What happens to bond strength as more electrons are shared?
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A coordinate bond involves the contribution of bonding electrons from two different atoms.
A coordinate bond involves the contribution of bonding electrons from two different atoms.
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What prefix is used to indicate two atoms of an element in a molecular naming convention?
What prefix is used to indicate two atoms of an element in a molecular naming convention?
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The bond length is __________ as the bond strength increases.
The bond length is __________ as the bond strength increases.
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Which of the following is an example of a compound with a dative bond?
Which of the following is an example of a compound with a dative bond?
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Match the following prefixes with their corresponding number:
Match the following prefixes with their corresponding number:
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What is the representation used for a coordinate bond in a diagram?
What is the representation used for a coordinate bond in a diagram?
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Ionic substances typically use prefixes in their names.
Ionic substances typically use prefixes in their names.
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What is the electron domain geometry for a molecule with 4 electron pairs?
What is the electron domain geometry for a molecule with 4 electron pairs?
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A molecule with 3 bonding electron domains and 1 lone electron pair has a triangular planar shape.
A molecule with 3 bonding electron domains and 1 lone electron pair has a triangular planar shape.
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How many degrees are the bond angles in a tetrahedral molecule?
How many degrees are the bond angles in a tetrahedral molecule?
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A molecule with 2 electron domains has a ______ shape.
A molecule with 2 electron domains has a ______ shape.
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Match the number of electron domains with their corresponding geometry:
Match the number of electron domains with their corresponding geometry:
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Which of the following shapes is observed in a molecule with 5 bonding electron domains?
Which of the following shapes is observed in a molecule with 5 bonding electron domains?
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Lone pairs always increase bond angles in molecular geometry.
Lone pairs always increase bond angles in molecular geometry.
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What shape results from 4 electron pairs where 1 is a lone pair?
What shape results from 4 electron pairs where 1 is a lone pair?
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For a molecule with 6 electron domains, the geometry is ______.
For a molecule with 6 electron domains, the geometry is ______.
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Match each shape to the corresponding electron domain arrangement:
Match each shape to the corresponding electron domain arrangement:
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What defines a covalent bond?
What defines a covalent bond?
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A single covalent bond involves the sharing of four electrons.
A single covalent bond involves the sharing of four electrons.
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What is electronegativity?
What is electronegativity?
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The shape of water (H2O) is described as _______.
The shape of water (H2O) is described as _______.
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Match the following types of bonds with their correct descriptions:
Match the following types of bonds with their correct descriptions:
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Which of the following molecules has a trigonal planar shape?
Which of the following molecules has a trigonal planar shape?
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Resonance structures indicate that a molecule has two distinct types of bonding.
Resonance structures indicate that a molecule has two distinct types of bonding.
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Define a polar covalent bond.
Define a polar covalent bond.
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Study Notes
Covalent Bonding
- Covalent bonding occurs when atoms share electrons to achieve a stable electron configuration
- Atoms gain stability by sharing electrons, rather than losing or gaining them (as in ionic bonding).
- Covalent bonds are classified as single, double, or triple, depending on the number of shared electron pairs (2, 4, or 6 respectively).
- Bond strength and length are related to the number of shared electrons; more shared electrons increase bond strength but decrease the bond length.
Dative/Coordinate Covalent Bonds
- A dative bond is a type of covalent bond in which both electrons in the shared pair come from the same atom.
- Illustrated with examples like H₃O⁺ and NH₄⁺.
Bond Polarity and Electronegativity
- Electronegativity is the measure of an atom's ability to attract bonding electrons.
- Differences in electronegativity between atoms in a bond determine the polarity of the bond (nonpolar, polar, ionic). A greater difference results in a greater ionic character and a less electronegative atom will have a partial positive charge.
- Differences in electronegativity are often displayed using the Pauling scale.
Lewis Structures
- Lewis structures show the arrangement of atoms and valence electrons in a molecule or polyatomic ion.
- They illustrate covalent bonds as lines between atoms, and lone/non-bonding pairs as dots.
- Resonance structures, show resonance is a way of describing molecules which have more than one possible Lewis structure; the true structure is an intermediate form, known as a resonance hybrid.
Bond Length and Bond Strength
- Bond length is the distance between the nuclei of two bonded atoms.
- Bond strength (or bond enthalpy) is the energy required to break the bond.
- Bond length and strength are related; longer bonds have lower strength.
Molecular Shapes (VSEPR Theory)
- Valence Shell Electron Pair Repulsion (VSEPR) theory predicts molecular shapes by considering the repulsion between electron pairs around a central atom.
- Electron domains (both bonding and lone pairs) arrange themselves to maximize separation.
- Common shapes include linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral.
Molecular Polarity
- Polar molecules have a dipole moment, which is a measure of the polarity of the molecule.
- If the individual bond dipoles in a molecule cancel out, the molecule is nonpolar, if they don't, it will be polar.
- A molecule's polarity depends on both its bond polarity and its molecular geometry.
Resonance Structures
- Resonance structures are used when a single Lewis structure cannot adequately represent the bonding in a molecule.
- Multiple Lewis structures are drawn in these cases by shifting the locations of electrons and identifying resonance hybrids as the actual structure.
- The actual structure is a resonance hybrid, an intermediate form between all resonance formulas.
Exceptions to the Octet Rule
- The octet rule (8 valence electrons) is not always followed; some elements can have more or less than 8 valence electrons around the central atom in their structures.
- Incomplete octets are found in molecules with less than 8 electrons around the central atom.
- Expanded octets are found in molecules with more than 8 electrons around the central atom.
- Examples of elements/atoms that can show these exceptions: boron, phosphorus, and sulfur.
Valence Bond Theory
- Valence bond theory describes covalent bonding in terms of overlapping atomic orbitals forming molecular orbitals.
- Two types of bonds are important in the theory: sigma (σ) and pi (π) bonds.
- Sigma bonds result from end-to-end, or axial overlap of atomic orbitals.
- Pi bonds result from sideways, or lateral, overlap.
- Hybridization (mixing atomic orbitals to form new hybrid orbitals) explains more complex bonding scenarios, like double or triple bonds.
Hybrid Orbitals
- Hybrid orbitals are combinations of atomic orbitals that result when atoms form covalent bonds.
- Common types include sp, sp², and sp³.
- The number of hybrid orbitals formed corresponds to the number of atomic orbitals involved in the mixing/hybridization process: for example sp³ are formed when one 2s and three 2p orbitals mix to four equivalent sp³ orbitals. Each hybrid orbital contains one electron. These orbitals align in space to maximize the distances between each other, forming different geometries.
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Description
Explore the fundamental principles of covalent bonding, including the behavior of non-metal atoms, the octet rule, and Lewis structures. This quiz covers the stability of atoms, bonding characteristics, and the representation of electrons in chemical formulas. Test your understanding of these essential chemistry concepts!
