Chem Bonding Flashcards
What is the octet rule?
Atoms tend to gain, lose, or share electrons to attain a stable configuration of eight valence electrons.
How does a potential energy diagram explain bond formation?
As two atoms approach, their energy decreases due to attraction, reaching a minimum at the bond length, then increases due to repulsion.
What are the different types of chemical bonds?
Ionic, covalent, coordinate covalent, metallic, and hydrogen bonds.
What is an ionic bond?
A bond formed due to electrostatic attraction between oppositely charged ions.
Give examples of ionic bonds.
NaCl, MgO, CaF₂.
What are the characteristics of ionic compounds?
High melting/boiling points, crystalline solids, conduct electricity in molten or aqueous state.
What is the Born-Haber cycle?
A thermodynamic cycle used to calculate lattice energy of ionic compounds.
What is a covalent bond?
A bond formed by the sharing of electron pairs between atoms.
Give examples of covalent bonds.
H₂, O₂, CH₄, CO₂.
What are the characteristics of covalent compounds?
Low melting/boiling points, poor conductivity, soluble in nonpolar solvents.
What is a Lewis structure?
A diagram showing valence electrons as dots to represent bonding.
What is the VSEPR theory?
Valence Shell Electron Pair Repulsion theory predicts molecular shapes by minimizing electron pair repulsion.
What is bond polarity?
Unequal sharing of electrons in a covalent bond due to differences in electronegativity.
What is dipole moment?
A measure of the polarity of a molecule, represented as μ = q × d.
What are bond parameters?
Properties like bond length, bond angle, bond enthalpy, bond order.
How does VSEPR theory predict molecular geometry?
Electron pairs arrange to minimize repulsion, determining shape.
What is hybridization?
Mixing of atomic orbitals to form new hybrid orbitals with equivalent energy.
What is sp hybridization?
Linear arrangement of orbitals formed by one s and one p orbital, e.g., BeCl₂.
What is sp² hybridization?
Triangular planar arrangement formed by one s and two p orbitals, e.g., BF₃.
What is sp³ hybridization?
Tetrahedral arrangement of orbitals formed by one s and three p orbitals, e.g., CH₄.
What is dsp² hybridization?
Square planar arrangement formed by one d, one s, and two p orbitals, e.g., [Ni(CN)₄]²⁻.
What is dsp³ hybridization?
Trigonal bipyramidal hybridization formed by one d, one s, and three p orbitals, e.g., PCl₅.
What are sigma (σ) and pi (π) bonds?
σ bonds form by head-on overlap; π bonds form by sideways overlap of p orbitals.
How many sigma and pi bonds are in CH₄?
CH₄ has 4 sigma bonds and no pi bonds.
How many sigma and pi bonds are in C₂H₄?
Ethene (C₂H₄) has 5 sigma bonds and 1 pi bond.
How many sigma and pi bonds are in C₂H₂?
Ethyne (C₂H₂) has 3 sigma bonds and 2 pi bonds.
What is resonance?
Delocalization of electrons in a molecule represented by multiple Lewis structures.
Give examples of resonance.
CO₃²⁻, NO₃⁻, SO₂, benzene (C₆H₆).
What is molecular orbital theory (MOT)?
A theory describing bonding using molecular orbitals formed by atomic orbital overlap.
What is the molecular orbital configuration of H₂?
(σ1s)².
What is the molecular orbital configuration of N₂?
(σ2s)²(σ*2s)²(π2p)⁴(σ2p)².
What is the molecular orbital configuration of O₂?
(σ2s)²(σ2s)²(π2p)⁴(σ2p)²(π2p)².
What is the molecular orbital configuration of F₂?
(σ2s)²(σ2s)²(π2p)⁴(σ2p)²(π2p)⁴.
What is bond length?
The equilibrium distance between the nuclei of two bonded atoms.
What is bond order?
The number of bonding electron pairs between two atoms.
How is bond order related to bond length?
Higher bond order means shorter bond length and stronger bonds.
What is hydrogen bonding?
A weak interaction between a hydrogen atom and an electronegative atom like N, O, or F.
Give examples of hydrogen bonding.
Water (H₂O), ammonia (NH₃), hydrogen fluoride (HF), DNA base pairing.
Why is NaCl an ionic compound?
Na donates one electron to Cl, forming Na⁺ and Cl⁻ ions held by electrostatic attraction.
Draw the Lewis structure of CO₂.
O=C=O (each oxygen has two lone pairs).
Why do ionic compounds have high melting points?
Strong electrostatic forces require high energy to break.
Calculate the bond order of N₂.
Bond order = (8-2)/2 = 3.
Which molecule has sp hybridization?
BeCl₂ (linear).
What is the shape of NH₃ based on VSEPR theory?
Trigonal pyramidal.
Why is water bent but CO₂ is linear?
H₂O has lone pairs on oxygen, CO₂ does not.
Why does diamond not conduct electricity but graphite does?
Diamond has all sp³ bonds; graphite has delocalized π electrons.
Why is O₂ paramagnetic but N₂ is diamagnetic?
O₂ has unpaired electrons in π* orbitals; N₂ has all electrons paired.
Explain hydrogen bonding in HF.
H forms a weak bond with F of another HF molecule.
