Bonding: Electronegativity/ forces between molecules Flashcards
what is electronegativity?
measure of the tendency of an atom to attract a bonding pair in a covalent bond
what is electron density?
the probability of finding an electron in a particular volume of space
what scale is used to measure electronegativity?
Pauling scale - 0 to 4 (where 4 is the greatest electronegativity)
list 3 factors which will affect the electronegativity?
- nuclear charge
- shielding
- distance from nucleus
what is the trend of electronegativity across a period?
electronegativity increases - increased nuclear charge
what is the trend of electronegativity down a group?
electronegativity decreases - more shielding/ greater distance from nucleus
what are the most electronegative atoms?
fluorine, oxygen, nitrogen, chlorine
how are electrons shared in a covalent molecule of identical atoms?
shared equally - non-polar
why are electrons not shared equally in a covalent bond of different electrons?
different electronegativity
how does difference in polarity affect electronegativity?
the greater the difference, the more polar the bond is
name three types of intermolecular forces
- van der Waals forces
- permanent dipole-dipole attraction
- hydrogen bonding
what is a dipole?
different in charge between two atoms due to shift in electron density in bond (different electronegativity)
are van der Waals forces strong?
not they are weak due to the constant movement of electrons inducing temporary dipoles
how does the size of a molecule affect van der Waals forces?
the greater the molecule the stronger the forces because there will be more electrons
why are dipole-dipole forces stronger than van der Waals forces?
polar bonds have overall dipole
