Chapter 4 Flashcards
Why is molecular structure so important?
small changes in the 3D structure can completely change chemical properties
What does teratogenic mean?
it harms the fetus
What is the VSEPR model used for?
used to predict the structure of molecules
What is the difference in electron arrangement shape and molecular shape?
electron arrangment shape takes all regions of electron density into consideration whereas the molecular shape on takes into consideration how many bond pairs and lone pairs their are separately
Why do molecules conform to a structure?
to maximize the distance between electrons
How do you figure out the number of regions of electron density?
look at the central atom, see where there are bonds and lone pairs, add it all up
Does a double bond or triple bond count as 1 region of electron density or multiple regions of electron density?
the double and triple bonds count as 1 region of electron density
What is the electron arrangement structure for 2 regions of electron density?
linear
o - o - o
What is the electron arrangement for 3 regions of electron density?
trigonal planar
o
I
o
/ \
o oWhat is the electron arrangement for 4 regions of electron density?
tetrahedral
o
l
o
/ l \
o o o
What is the electron arrangement for 5 regions of electron density?
trigonal bipyramidal (mix of 1 and 2 )
What is the electron arrangement for 6 regions of electron density?
octahedral (3 linears intersecting at central atom)
What does the electron arrangement describe?
describes the general structure of the molecule
What does the molecular structure describe?
location of bonds/atoms only since lone pairs require more space to move around
What are bonding electrons?
shared between 2 atoms and are attracted to the nuclei
What are non-bonding electrons?
affiliated with 1 atom and attracted to 1 nucleus
In AXnEm notation, what does the A stand for?
central atom (just written as A)
In AXnEm notation, what does the Xn stand for?
number of bonds around central atom (written as X)
#In AXnEm notation, what does the Em stand for?
number of lone pairs around central atom (written as E )
m
What is the electron arrangement and molecular structure for AX2?
linear and linear
What is the electron arrangement and molecular structure for AX3?
trigonal planar and trigonal planar
What is the electron arrangement and molecular structure for AX2E1?
trigonal planar and bent
What is the electron arrangement and molecular structure for AX4?
tetrahedral and tetrahedral
What is the electron arrangement and molecular structure for AX3E1?
tetrahedral and trigonal pyramidal
What is the electron arrangement and molecular structure for AX2E2?
tetrahedral and bent
What is the electron arrangement and molecular structure for AX5?
trigonal bipyramidal and trigonal bipyramidal
What is the electron arrangement and molecular structure for AX4E1?
trigonal bipyramidal and seesaw
What is the electron arrangement and molecular structure for AX3E2?
trigonal bipyramidal and T-shape
What is the electron arrangement and molecular structure for AX2E3?
trigonal bipyramidal and linear
What is the electron arrangement and molecular structure for AX6?
octahedral
What is the electron arrangement and molecular structure for AX5E1?
octahedral and square pyramidal
What is the electron arrangement and molecular structure for AX4E2?
octahedral and square planar
What is the first step in determining molecular structure?
drawing the lewis dot diagram
What is the second step in determining molecular structure?
count the number of regions of electron density around the central atom
What is the third step in determining molecular structure?
arrange the attached atoms or groups of atoms around the central atom in a way that maximizes the distances of electrons
What is the fourth step in determining molecular structure?
determine the name of the molecular structure
How do you consider the “central” atom with a compound that has more than 1 central atom?
consider each center individually
What is the electronegativity difference between polar covalent bonds?
0.4 to 1.7
How do notate that one atom is more electronegative than the other?
less electronegative atom -l—-> more electronegative atom
What are dipole moments?
unequal distribution of electrons indicating polar bonds
When trying to figure out if a compound is overall polar or nonpolar, what do you do?
draw the lewis dot diagram and see the distribution of electrons
Is a molecule polar or nonpolar if there is an equal distribution of electrons from atoms in the same group?
non-polar molecule
Is a molecule polar or nonpolar if there is an unequal distribution of electrons from atoms of different groups?
polar molecule
Is a molecule polar or nonpolar if there is an unequal distribution of electrons from atoms of different and same groups?
polar molecule
What is the bond of an atom in terms of being polar and nonpolar?
bond of an atom being nonpolar or polar refers to the electronegativity (atoms from different groups)
What is the overall molecular-ness of an atom being polar or nonpolar telling you to look at?
looking at the distribution of electrons (if it is equal or not)
