6.2 Electronegativity and polarity Flashcards
what is electronegativity?
the ability for a a bonded atom to attract a shared pair of electrons in a covalent bond
what is the electronegativity when the bonded atoms are the same element?
the shared pair of electrons are shared eqaully
what is the electronegativity when the bonded atoms are of different elements?
a shared pair of electrons are attracted more to one nucleus than the other
what happens if the electronegativity of an atom is greater than 1.8?
the bond formed is ionic as an atom has gained control of the shared pair of electrons which makes it negatively charged
what is a non-polar bond?
when the bonded electron pair is shared equally between the bonded atoms
these molecules ARE NOT POLAR
when does a non-polar bond form?
when the bonded atoms are the same
when the bonded atoms have a very similar electronegativity
what is a polar bond?
when the bonded electron pair is shared unequally between the bonded atoms
when does a polar bond form?
when the bonded atoms are different
when the bonded atoms have very different electronegativity
why is HCl polar?
chlorine has a larger negativity than hydrogen so attracts the bonded electron pair more
this leads to the chlorine being delta -ve and the hydrogen being delta +ve
what is a dipole?
the separation of opposite charges
what can happen if a molecule has more than one dipole?
the dipoles can combine to form a larger dipole
the dipoles can cancel each other out
what makes a molecule asymetrical?
if it has a lone pair
if it has no lines of symmetry
how is water polar?
oxygen is more electronegative than hydrogen
a permanent dipole is formed
oxygen attracts the bonded pair of electrons more than the hydrogen
how is carbon-dioxide non-polar?
oxygen is more electronegative than carbon
a permanent dipole is formed
the two dipoles are in opposite directions so cancel each other out
therefore the dipole is zero
how are polar solvents soluble?
as water has atoms which are partially positive or partially negative, they can attract the positive and negative ions in an ionic lattice
