Shapes of molecules and ions Flashcards
What are the 5 main shape names?
- Linear shape
- Trigonal planar
- Tetrahedral
- Trigonal bipyramid
- Octahedral
How can you predict the shape of a simple covalent molecule?
You can predict by the number of electrons around an atom. Each electron pair will repel all the other pairs of electrons. Therefore they will take positions as far apart as possible to minimise repulsion
What is the positioning of electrons far apart and repulsion between electrons referred to as? (theory)
The electron repulsion theory
What is the shape name of a molecule with two electron pairs and a bond angle of 180 degrees?
The shape name given to a molecule with two electron pairs would be a LINEAR shape
What is the bond angle of a LINEAR shape?
What are a few examples of linear shaped molecules?
180 degrees
Carbon dioxide
Beryllium chloride
Beryllium fluoride
What is the shape name of a molecule with three electron pairs?
If the shape has three electron pairs how many ELECTRONS does the shape have?
The shape name given to a molecule with three electron pairs would be a TRIGONAL PLANAR shape
There are 6 electrons within this shape type
What is the bond angle of a TRIGONAL PLANAR shape?
120 degrees
What is the bond angle of a TETRAHEDRAL shape?
109.5 degrees
What is the shape name of a molecule with four electron pairs?
If the shape has 4 electron pairs how many ELECTRONS does the shape have?
The shape name given to a molecule with four electron pairs would be a TETRAHEDRAL shape
There are 8 electrons within this shape
What is the shape name of a molecule with 5 electron pairs?
If the shape has 5 electron pairs how many ELECTRONS does the shape have?
The shape name given to a molecule with five electrons pairs would be a TRIGONAL BIPYRAMID shape
There are 10 electrons within this shape
What is the shape name of a molecule with 6 electron pairs?
The shape name given to a molecule with six electron pairs would be an OCTAHEDRAL shape
What is the bond angle of a OCTAHEDRAL shape?
90 degrees
Do bonding rules change or stay the same when molecules with lone pairs of electrons are introduced?
Bonding rules change when molecules with lone pairs of electrons are introduced
What affect do lone electron pairs have on the shape of molecules?
Lone electron pairs provide additional repulsive forces which change the bond angle
What is the bond angle of a TRIGONAL BIPYRAMIDAL shape?
120 degrees
For each lone electron pair, how much is the covalent bond reduced?
For each lone electron pair, the covalent bond is reduced by 2.5 degrees
Order these in the increase of repulsion:
1. Lone pair - bonded pair
2. Lone pair - lone pair
3. Bonded pair - bonded pair
- Bonded pair - Bonded pair
- Bonded pair - Lone pair
- Lone pair - Lone pair
