Topic 7 VSEPR Flashcards
What is the aim of the topic on Valence Shell Electron Pair Repulsion Theory (VSEPR)?
To draw Lewis structures, understand VSEPR, and determine the shape of a molecule.
What is ionic bonding?
Electrostatic attraction between atoms.
What is covalent bonding?
Sharing of electrons.
What is metallic bonding?
Metal atoms bonded to several other atoms.
Define electronegativity.
Ability of an atom to attract a shared pair of electrons in its combined state.
Define electropositivity.
Ability of an atom to withdraw a shared pair of electrons in its combined state.
What does Lewis structure represent in covalent bonding?
A covalent bond where two atoms are held together by a pair of shared electrons.
How are double and triple bonds represented in Lewis structures?
Double bond: two lines. Triple bond: three lines.
What role does the shape of a molecule play?
It plays an important role in its reactivity.
What determines the shape of a molecule according to VSEPR?
Electron pairs repel each other and are distributed as far apart as possible.
What is an electron domain?
The region in which electrons are most likely to be found, including lone pairs and bonds.
What is the best arrangement of electron domains according to VSEPR?
The arrangement that minimizes the repulsions among them.
What is the general formula for molecules with no lone pairs on the central atom?
ABx, where x is an integer usually 2 to 6.
How does the presence of lone pairs affect molecular shape?
Lone pairs occupy more space and experience greater repulsion than bonding pairs.
What is the order of repulsion forces in VSEPR theory?
Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding pair.
What are the three steps to predicting the shape of a molecule?
- Draw a Lewis structure
- Count electron pairs around the central atom
- Distribute atoms and lone pairs as far apart as possible.
What is the shape of ammonia (NH3)?
Pyramidal.
What is the shape of water (H2O)?
Bent or V-shaped.
What is the significance of bond angles in VSEPR theory?
Bond angles are determined by the arrangement of electron domains around the central atom.
What should be noted about charges in oxyanions?
Negative charges usually reside on the oxygen atoms.
How do you treat double and triple bonds in VSEPR calculations?
Treat them as single bonds.
What is hybridization of the central atom?
The mixing of atomic orbitals to form new hybrid orbitals for bonding.
What are the hybridizations associated with sp, sp2, and sp3?
- sp: linear
- sp2: trigonal planar
- sp3: tetrahedral.
