Electronegativity and bond polarity

Question 1

What is a covalent bond? (memorise)

Answer 1

strong electrostatic attraction between a SHARED PAIR of electrons and nuclei of bonded atoms

Question 2

Are electrons shared, donated or given in covalent bond?

Answer 2

SHARED

Question 3

What is the definition of electronegativity? (memorise)

Answer 3

measure of the attraction
of a bonded atom
for the pair of electrons in a covalent bond

Question 4

On which scale is the electronegativity measured? Who is the scale named after?

Answer 4

Pauling scale
Linus Pauling ( A chemist )

Question 5

What are the 2 ways electronegativity increases through in the periodic table?

Answer 5

Up a group
Across a period
(In all directions towards fluorine which is at the top of the group far right at the end of a period)

Question 6

Why does electronegativity increase across a period?

Answer 6

• the charge on a nucleus increases across a period
• The number of protons in a nucleus of an atom increases and therefore the strength of the attraction of the nucleus of the bonded atom for the electrons increases

Question 7

Why does electronegativity increases up a group?

Answer 7

• moving down a group, the number of shells increases, so the distance between the nucleus of an atom and the electrons increases and bonding pair of electrons are farther away from the nucleus, so attraction of nucleus for electrons in the outer shell decreases. (simply, the less number of shells, the closer the electrons to the nucleus and the stronger the attraction between them and the electronegativity as well.)

Question 8

what are polar bonds

Answer 8

covalent bonds
where a shared pair of electrons is attracted more towards one atom forming unequal distribution of charges on both atoms

Question 9

what is a dipole

Answer 9

a dipole occurs when electrons are unshared unequally between atoms in a covalent bond and therefore partial charges are formed on the atoms

Question 10

What are non polar bonds?

Answer 10

bonds that occur when atoms have equal or almost equal electronegativity and attract electrons equally and share them fairly and a perfectly covalent bond is formed.

Question 11

what is a polar bond? Keep in mind manifest your understanding

Answer 11

a covalent bond that occurs when atoms with a difference in electronegativity share a pair of electrons and the electrons are shared unequally and unfairly where they are attracted more towards the atom with higher electronegativity and form partial charges at both the atoms, since atoms form partial charges at both ends they form “poles” and therefore form a dipole. The covalent formed is polarised.

Question 12

What is the definition of electron density?

Answer 12

probability of finding electrons at a particular position in space

Question 13

The more lines closer together, the more ……….. an atom is

Answer 13

electron dense

Question 14

Do bonds exist as discrete ionic bonds or as a spectrum? what is the spectrum made of?

Answer 14

as a spectrum consisting of
polar covalent bonds
non polar covalent bonds
ionic bonds

Question 15

Is the non polar covalently bonded molecule electronically symmetrical or not?

Answer 15

yes electronically symmetrical

Question 16

When a molecule is electronically symmetrical the dipole effect is cancelled out (t/f)

Answer 16

True

Question 17

what are symmetrical shapes?

Answer 17

Linear, trigonal planar, tetrahedral

Question 18

what happens if a molecule is polar covalent but is electronically symmetrical?

Answer 18

the dipole effect cancels out and the molecule is non polar

Question 19

definition of term polarization

Answer 19

Bond is polarized where electrons are unequally shared between the covalently bonded atoms and therefore charge unequally distributed and partial charge formed on each of the bonded atoms. The bond is polarized.

Question 20

define electronegativity

Answer 20

The ability of an atom to attract a shared pair of electrons to itself in a covalent bond