3.1.3 (b&s) bond polarity and electronegativity Flashcards
are covalent bonds polar or non-polar?
they can be both
what can cause covalent bonds to become polarised?
what does this cause?
differences in electronegativity
causing a dipole between the two atoms
what is a charge cloud?
An area around the atom, where are you have a good chance of finding an electron pair
definition: electronegativity
The ability of an atom to attract the pair of electrons in a covalent bond towards itself
How do you measure electronegativity?
using the Pauling scale
What element is the most electronegative?
fluorine
The closer the element is fluorine on the periodic table, the more electronegative, it will be
What are the two transit electronegativity?
- across a period:
- The electronegativity value increases across a period
- as the nuclear charge increases the size of the atom decreases?
- There is a greater attraction between the nucleus of the pair of electrons of the covalent bond - Down a group:
- The electronegativity value decreases down the group
- the effects of the increase in nuclear charge is less than the effect of the increased atomic radius of the shielding effect of the inner electrons
what is a non-polar bond formed
if the two atoms of the covalent bonds are the same or similar electronegativity values
then the covalent bonds will have a symmetrical electron cloud distribution
And the bond is non-polar
how are polar bonds formed?
An asymmetrical distribution of the electron cloud in a covalent bond occurs when two atoms have different electronegativity values
This results in a polar band
The more electronegative element will have what?
A greater attraction for the pair of electrons in a covalent bond
The greater the difference in electronegativity the what?
more polar the bond
