5.1 VSEPR model Flashcards
what does VSEPR stand for?
valance shell e- pair repulsion
what is the name given to the 3D arrangement of atoms in a molecule
molecular structure
when is VSEPR best utilized?
to predict the 3D geometry of molecules formed from nonmetals
the main idea of VSEPR
is to minimize e- pair repulsions
what is the degree of the angles in a tetrahedral structure?
109.5
when should prs of e-‘s be arranged tetrahedrally?
when there are 4 prs of e-‘s around an atom
what is the first step in a VSEPR model?
draw the lewis structure
what is the 2nd step to a VSEPR model?
count the e- pairs and arrange them in a way that minimizes repulsion (put them as far apart as possible)
what is the 3rd step in a VSEPR model?
determine the positions of the atoms from the WAY the e- pairs are shared
when does a molecular structure VSEPR model get named?
after the positions of the atoms is determined in step 3
which requires more room? bonding pairs or lone pairs?
lone pairs
because lone pairs require more room than bonding pairs, what happens to the angles between the bonding pairs?
they get compressed to give the lone pairs more space on the orbitals of the atom they belong to.
what is the arrangement of 2 e- prs around an atom that yields minimum repulsion
linear
180 degrees
what is the arrangement of 3 e- prs around an atom that yields minimum repulsion
Trigonal planar
120 degrees
the tetrahedral arrangement of e- pairs is used for how many e- pairs?
4
109.5 degrees
the trigonal bipyramidal arrangement of e- pairs is used for how many e- pairs?
5
120/90 degrees
the octahedral arrangement of e- pairs is used for how many e- pairs?
6
90 degrees
what is the molecular structure of a molecule with 4 bonding e- pairs?
tetrahedral
what is the molecular structure of a molecule with 3 bonding e- pairs and 1 lone pr?
trigonal pyramid
what is the molecular structure of a molecule with 2 bonding e- pairs and 2 lone e- prs?
V-shaped (or bent)
what is the molecular structure of a molecule with 5 bonding e- pairs?
trigonal bipyramid
the see-saw structure is seen in molecules with how many bonding and lone pairs?
4 bonding
1 lone pair
the T-shaped structure is seen in molecules with how many bonding and lone e- prs?
3 bonding
2 lone prs
what are the possible molecular structures for molecules with 4 e pairs?
tetrahedral
trigonal pyramid
v-shaped (or bent)
what are the possible molecular structures for molecules with 5 e- pairs?
trigonal bipyramidal
see-saw
t-shaped
linear
in VSEPR model, a double bond is counted as
on effective pair
when a molecule exhibits resonance, which resonance structure should be used to predict the molecular structure in the VSEPR model?
any of them
what degree angle provides lone pairs with enough space so that distortions do not occur?
120
the mixing of the native atomic orbitals to create special orbitals for bonding
hybridization
sp3 hybridization or saying an atom is sp3 hybridized means
its orbitals formed from 1 2s and 3 2p orbitals (s1p3)
whenever a set of equivilent tetrahedral atomic orbitals is required by an atom in a molecule, the model assumes that the atom adopts a set of ___ orbitals; the atom is ____ ________
sp3
sp3 hybridized
