Polar and non-polar molecules

Question 1

What is the main property of an atom associated with the polarity of a molecule?

Answer 1

Electronegativity.

Atoms with high electronegativities attract the electron density towards themselves, increasing the polarity of a bond

Question 2

Which is the physical definition used to study the polarity of a bond?

Answer 2

Dipolar moment.

When two atoms have different electronegativity values, the dipolar moment increases towards the most electronegative.

Question 3

What type of molecules are always non-polar?

Answer 3

Symmetrical molecules.

When the main atom has a plane of symmetry, the dipolar moments are canceled and the molecule has no polarity.

Also, diatomic molecules like N2 or O2.

Question 4

H2O is polar or non-polar?

Answer 4

Polar.

Even though the oxygen is bonded with two hydrogens, it has two pairs of electrons with dipole moments that point in different directions. (Photo of the molecule)

Question 5

CH4 is polar or non-polar?

Answer 5

Non-polar.

The carbon is bonded to four equal atoms (H), so the dipole moments cancel each other.