Bonding and Structure Flashcards
What is covalent bonding
Sharing of outer electrons
Electrostatic attraction between the shared electrons and the positive nucleus
Dative/Coordinate bonds meaning
ONE atom donates 2 electrons to an atom or ion
Why do molecules have specific shape with specific angles
Bonds repel each other equally.
Bonds contain electrons so they will want to be as far as possible
2 BP
0 LP
Linear
180 degrees
3 BP
0 LP
Trigonal planar
120
4 BP
0 LP
Tetrahedral
109.5
5 BP
0 LP
Trigonal bipyramidal
90 degrees, 120 degrees (3D)
6 BP
0 LP
Octahedral
90 degrees
3 BP
1 LP
Trigonal pyramidal
107
2 BP
2 LP
Bent
104.5
3 BP
2 LP
Trigonal planar
120
4 BP
2 LP
Square planar
90
What is electronegativity
The ability for an atom to attract electrons towards itself in a covalent bond
How can covalent bonds be polar
If the atoms attached to it has different electronegativity
What bonds are non-polar
Hydrocarbons
Atoms bonded with the same or similar electronegativity
What leads to polar molecules
Uneven distribution of charge eg H2O
What happens during London forces
Occurs as electrons in a molecule or atom move from an end to another
Example of induced dipole-dipole
Iodine, crystal structure
What holds a London force structure
Weak induced dipole-dipole holds molecules
Stong covalent bonds hold the atoms
What does a bigger molecule/atom mean for London forces
More induced
As there are larger electron clouds
Why do branched hydrocarbons have lower BP
Can’t pack close together as close
Weakens the induced dipole-dipole forces between the chains.
Where does permanent dipole-dipole occur
Interactions exist in molecules with a polarity
Weak electrostatic forces that exist between the molecules with polarity
What is hydrogen bonding
Strongest intermolecular force that occurs when you have very electronegative elements
Bonds with lone pair on nitrogen, oxygen or fluorine
What other bonds does hydrogen bonding have
Induced dipole-dipole
Permanent dipole-dipole
