Shapes of molecules Flashcards
What is the order of (electron) repulsion starting from the highest?
- lone pair + lone pair
- lone pair + bond pair
- bond pair + bond pair
Why do lone pairs have the highest repulsion force?
Because they have a more concentrated electron charge cloud compared to bonding pairs.
What happens when electrons get too closer to one another?
They repel
What is electronegativity?
The power of an atom to attract the pair of electrons in a covalent bond toward itself.
What is the most electronegative element in the periodic table?
Fluorine (4.0)
What are the 3 factors that affect electronegativity?
- Nuclear charge
- Atomic radius
- Shielding
How does nuclear charge affect electronegativity?
- An increased number of protons results in an increase of nuclear attraction.
- An increased nuclear attraction = increased electronegativity
How does atomic radius effect electronegativity?
-The further away from the nucleus, the less strongly attracted the electrons are.
- Decreased electronegativity
How does shielding effect electronegativity?
- Filled energy levels can shield the effect of the nuclear charge causing the electrons to be LESS ATTRACTED to the nucleus.
- The more inner shells and sub shells results in a decreased electronegativity.
When does a non-polar covalent bond occur?
When the two atoms in a covalent bond have the SAME electronegativity (meaning the two electrons are shared equally).
When does a polar covalent bond occur?
When the two atoms in a covalent bond have a DIFFERENT electronegativity (meaning electrons are shared unequally).
What is the dipole moment?
The measure of how POLAR a bond is.
What bond angle is linear?
180 degrees
What bond angle is Trigonal planar?
120 degrees
What bond angle is tetrahedral?
109.5 degrees
