6. Shapes of molecules and intermolecular forces Flashcards
What do electron pairs do because of their negative charge?
They repel each other
What does the number of bonded and lone pairs determine?
The shape of a molecule
Which two pairs of electrons are the most repelling?
2 lone pairs
Which two pairs of electrons are the least repelling?
2 bonded pairs
Why do lone pairs repel more strongly than bonded pairs?
Because lone pairs are slightly closer to the central atom and occupies (佔用) more space.
What is the name of shape that has 4 bonded pairs and 0 lone pairs?
Tetrahedral
What is the bond angle of a tetrahedral compound?
109.5°
How to draw a tetrahedral compound (in terms of lines and number of lone pairs) ?
2 solid lines, 1 solid wedge, 1 dotted wedge and 0 lone pairs (crosses).
What is an example of a tetrahedral compound?
CH4 (methane)
What is the name of shape that has 3 bonded pairs and 1 lone pair?
Pyramidal
What is the bond angle of a pyramidal compound?
107°
How to draw a pyramidal compound (in terms of lines and number of lone pairs) ?
1 solid line, 1 solid wedge, 1 dotted wedge and 1 lone pair (crosses).
What is an example of a pyramidal compound?
NH3 (ammonia)
What is the name of shape that has 2 bonded pairs and 2 lone pair?
Non-linear
What is the bond angle of a non-linear compound?
104.5°
How to draw a non-linear compound (in terms of lines and number of lone pairs) ?
1 solid line, 1 solid wedge, 0 dotted wedge and 2 lone pairs (crosses).
What is an example of a non-linear compound?
H2O (water)
What is the name of shape that has 2 bonding regions?
Linear
What is the bond angle of a linear compound?
180°
How to draw a linear compound (in terms of lines and number of lone pairs) ?
All bonds are drawn in solid lines and 0 lone pairs (crosses) needed.
What is an example of a linear compound?
CO2 (carbon dioxide)
What is the name of shape that has 3 bonding regions?
Trigonal planar
What is the the bond angle of a trigonal planar compound?
120°
How to draw a trigonal planar compound (in terms of lines and number of lone pairs) ?
All bonds are drawn in solid lines and 0 lone pairs (crosses) needed.