VSEPR Flashcards
What is a molecules shape determined by?
bond lengths and bond angles
bond angle definition
the angle formed between the nuclei of two atoms that surround the central atom of a molecule
What does VSEPR theory stand for?
Valence shell electron pair repulsion theory
What is VSEPR?
a theory used to explain the 3D shape of molecules
What does VSEPR say?
the idea is that electron pairs both shared and lone pairs in the valence shell of an atom want to be as far apart from each other as possible (they repel each other because of similar charge)
the 3-D structure is determined by minimizing repulsion of electron pairsWhat
What is an electron group?
a single bond, double bond, triple bond or lone pair
What are the two types of electron pairs
bonding pairs and lone pairs
When will the electron shape be the same as the molecule shape?
when all electron groups around a central atom are all bonding electrons (NO LONE PAIRS)
When is the electron shape different from the molecule shape
when one or more of electron groups that surrounds the central atom is a lone pair
What are the three types of repulsive forces in molecules that have at least one lone pair?
- Bonding pairs (BP-BP)
- Lone pairs (LP-LP)
- Bonding and Lone pairs (BP-LP)
Lone pairs (LP_ of electrons spread out more than bonded pair (BP) and therefore repel more, so what is the heirarchy?
LP-LP > LP-BP > BP-BP
What is the size angle for tetrahedral?
109.5
What are the 5 possible shapes of molecules?
- linear
- trigonal planar
- bent/angular
- tetrahedral
- trigonal pyramidal
What is the A in AXE notation?
the central atom
What is the X in AXE notation?
attached atoms
