Chem bonding bookbacks Flashcards
Why do atoms form chemical bonds?
To attain a stable electronic configuration by lowering their potential energy.
What is the octet rule?
Atoms tend to gain, lose, or share electrons to achieve eight valence electrons, like noble gases.
Why do noble gases not form chemical bonds easily?
They already have a full valence shell, making them stable and unreactive.
How does the potential energy diagram explain bond formation?
As two atoms approach their energy decreases until an optimal bond length is reached, after which repulsion increases.
What are the main types of chemical bonds?
Ionic, covalent, and metallic bonds.
How does an ionic bond form?
Through the transfer of electrons from a metal to a non-metal creating oppositely charged ions.
What are the characteristics of ionic compounds?
High melting and boiling points, solubility in water and electrical conductivity in molten or aqueous states.
Why do ionic compounds conduct electricity in molten state but not in solid state?
In solid state, ions are fixed, while in molten state, they are free to move and conduct electricity
What is a covalent bond?
A chemical bond formed by the sharing of electron pairs between atoms.
How is a covalent bond represented using Lewis structures?
By dots representing valence electrons or lines representing shared electron pairs.
What is the difference between polar and nonpolar covalent bonds?
Polar covalent bonds have an unequal sharing of electrons while nonpolar covalent bonds share electrons equally.
Why is H₂O a polar molecule while O₂ is nonpolar?
H₂O has an asymmetric electron distribution, while O₂ has equal electron sharing.
What is the Born-Haber cycle used for?
To calculate lattice energy of ionic compounds using different enthalpy changes.
Why is the lattice energy of NaCl high?
Due to strong electrostatic attraction between Na⁺ and Cl⁻ ions.
How does the VSEPR theory help predict molecular shape?
It states that electron pairs arrange themselves to minimize repulsion determining molecular geometry.
What shape does NH₃ have according to VSEPR theory?
A trigonal pyramidal shape due to one lone pair on nitrogen.
What is hybridization?
The mixing of atomic orbitals to form new hybrid orbitals with specific shapes and energy levels.
What type of hybridization is seen in CH₄, BF₃, and BeCl₂?
CH₄: sp³ (tetrahedral), BF₃: sp² (trigonal planar), BeCl₂: sp (linear).
What is a sigma (σ) bond?
A bond formed by head-on overlap of orbitals allowing free rotation around the bond axis.
What is a pi (π) bond?
A bond formed by sideways overlap of p orbitals, restricting rotation.
Why is a sigma bond stronger than a pi bond?
Head-on overlap in sigma bonds results in greater electron density between nuclei.
What is resonance?
When a molecule has multiple valid Lewis structures that differ only in electron placement.
Why does CO₃²⁻ exhibit resonance?
The double bond can be placed between different oxygen atoms leading to delocalized electrons.
What is molecular orbital theory (MOT)?
A theory describing bonding in terms of molecular orbitals formed by atomic orbitals.
