Shapes Of Molecules And Ions Flashcards
What is the electron pair repulsion theory?
An electron has a negative charge, so electron pairs repel one another.
Why are electrons arranged as far apart as possible?
Because the electrons repel each other.
What determines the shape of the molecule or ion?
The electron pairs surrounding a central atom.
What minimises repulsion and holds the atoms in a definite shape?
The arrangement of electron pairs.
What does a solid line represent?
A bond in the plane of the paper.
What does a solid wedge represent?
A bond coming out of the plane of the paper.
What does a dotted wedge represent?
A bond going into the plane of the paper.
Which type of electron pair is slightly closer to the central atom?
A lone pair of electrons.
Which type of electron pair occupies more space?
A lone pair of electrons.
Does a lone pair of electrons repel more strongly or weakly?
Strongly- for reasons mentioned previously.
Why is the bond angle smaller between bonded pairs of electrons?
The lone pairs repel each other more and therefore cause the bonded pairs to be closer together.
What is the bond angle reduced by for each lone pair?
2.5 degrees
How many bonded pairs are in a tetrahedral?
4
How many lone pairs in a tetrahedral?
0
What is the bond angle of a tetrahedral molecule?
109.5 degrees
Give an example of a tetrahedral molecule?
Methane
How many bonded pairs does an pyramidal shaped molecule have?
3
How many lone pairs of electrons does a pyramidal shaped molecule have?
1
Give an example of a molecule with a pyramidal shape.
Ammonia
What is the bond angle for pyramidal molecules?
107degrees
How many bonded pairs does a non-linear molecule have?
2
How many lone pairs does a non-linear molecule have?
2
What is the bond angle of non-linear molecules?
104.5 degrees
Give an example of a non-linear molecule.
H2O
In molecules containing multiple bonds, what is each multiple bond treated as?
A bonding region.
For how many bonded regions does a double bond count for?
1
Give an example of a linear molecule.
Carbon dioxide
What do electron pairs around the central atoms do?
Electron pairs around the central atom repel each other as far apart as possible.
What decreases the smaller bond angle?
The greater the number of electron pairs, the smaller the bond angle.
What is the bond angle of a linear molecule?
180 degrees
How many bonded electron pairs are in a linear molecule?
2
What is the bond angle of a trigonometry planar molecule?
120 degrees
How many bonded pairs of electrons are in a trigonal planar molecule?
3
How many lone pairs of electrons are in a linear molecule?
2
How many lone pairs of electrons are in a trigonal planar molecule?
1
How many bonded pairs of electrons are in an octahedral molecule?
6
How many lone pairs of electrons are in an octahedral molecule?
0
What is the bond angle of an octahedral molecule?
90 degrees
What is the shape of a SO4 2- ion?
Tetrahedral
What is the shape of a CO3 2- ion?
Trigonal planar
What is the shape of a NO3- ion?
Trigonal planar
What is the shape of an ammonium ion?
Tetrahedral
