Bonding and Structure & Intermolecular forces Flashcards
What is a Dative Covalent Bond?
A shared pair of electrons that has been provided by one of the bonding atoms only.
What is the angle and the shape of called when you have two bonding pairs?
Linear 180 degrees
What is the angle and shape when you have 3 bonding pair regions and 0 lone pair regions?
Trigonal Planar 120 degrees
What is the angle and shape when you have 2 bonding pair regions and 1 lone pair region
Non- linear 119 degrees
What is the angle and shape when you have 4 bonding pair regions
Tetrahedral 109.5 degrees
What is the angle and shape when you have 3 Bonding pair regions and 1 lone pair region
Trigonal Pyramidal 107 degrees
What is the shape and angle when you have 2 bonding regions and 2 lone regions?
Non- linear 104.5 degrees
What is the angle and shape when you have 6 bonding regions
Octahedral 90 degrees
How do we explain the shape of a molecule
Around the central atom there are …. bonding pairs and …. lone pairs.
Electron pair regions repel each other as far as possible and lone pairs of electrons repel more than bonding Pairs.
What is meant by electronegativity?
The ability of atom to attract a pair of electrons in a covalent bond.
How do we explain when a molecule has a permanent dipole but is non-polar overall?
The two dipoles act in opposite directions and therefore cancel each other out making it non-polar.
What is a dipole?
The separation of opposite charges.
What are the three types of intermolecular force?
Induced dipole-dipole forces
Permanent Dipole - Dipole
Hydrogen Bonds
Describe Induced dipole-dipole forces and how they come about.
Weakest type of intermolecular force .
Uneven distribution of electrons
creates an instantaneous dipole
This induces dipoles on a neighbouring molecule
the molecules attract
What is a Hydrogen bond?
Special Type of Permanent dipole- dipole force. Only occurs between Hydrogen and eiher F, O , N
Why does the boiling point increase down Group 7
Number of e- increases
Increases the induced dipole-dipole forces which are stronger
requires more energy to overcome
Explain the anomalous property of Ice being less dense than water
Freezing causes H bonds to extend forcing the water molecules further apart creating an open lattice so ice floats.
Why does ice have a higher melting point than expected?
More energy needed to overcome H bonds
What is meant by giant ionic lattice?
Regular arrangement of oppositely charged ions .
What is the structure of diamond?
Giant Covalent structure.
