3.1.3 (b&s) shapes of simple molecules and ions Flashcards
what are the outer electrons in simple covalent molecules and simple molecular ions arranged into?
Pairs
why are electron pairs as far apart as possible?
Because the electron pairs can be considered as clouds of electron density, which repel each other, so they are as far apart as possible
What does the repulsion between electron pairs dictate?
The shape of the molecule or ion
which dictates of the shape of the molecule or ion?
The repulsion between electron pairs
what is the bond angle and name of shape if the number of electron pairs is: 2
180°
Linear
what is the bond angle and name of shape if the number of electron pairs is: 3
120°
trigonal planar
what is the bond angle and name of shape if the number of electron pairs is: 4
109.5°
tetrahedral
what is the bond angle and name of shape if the number of electron pairs is: 5
120° and 90°
trigonal bypyramidal
what is the bond angle and name of shape if the number of electron pairs is: 6
90°
octahedral
how do you represent a bond going behind the plane of paper?
using a dotted/dashed line
how do you represent a bond coming out of the point of paper?
a shaded triangle
how do you represent a bond in the plane of paper?
An ordinary line
what happens to the shape if there are line pairs present?
The shape becomes distorted
do lone pairs or bond pairs have a greater repulsive power?
What does this mean?
lone pairs
This leads to a small reduction in the bond angle
what is the name of a shape and the bond angle with a molecule that has:
Bonded pairs : 3
Lone pairs : 1
trigonal bipyramidal
107°
