Question

What is the significance of an electronegativity difference of 1.7 between 2

atoms?
O A. It tells which atoms form positive ions and which atoms form
negative ions.
OB. It represents the boundary between what is considered to be an
ionic or a covalent bond.
C. It determines if the 2 atoms will react to form a molecule.
D. It identifies which metal atoms will join together to form metallic
bonds
Am

Answer 1

B. It represents the boundary between what is considered to be an ionic or a covalent bond.

Further explanation

Electronegativity is the ability of atoms to attract electrons, especially in covalent bonds (sharing of electron pairs)

In a periodic system, electronegativity increases in a group, from bottom to top, and in a period from left to right.

From this difference in electronegativity, we can determine the ionic compound, polar or non-polar

Pauling determined the electronegativity scale (based on bond energies), between 0.7 - 4 (Fluorine has the highest number of electronegativities: 4)

Polar covalent compounds have a large electronegativity difference, while nonpolar compounds have a small electronegativity difference.

We can use the difference in electronegativity between the 2 bonded atoms to determine their polarity

• <0.5: covalent non polar
• 0.5- 1.7: covalent polar
• > 1.7 : ion

Example

• H₂O

H = 2.1

O = 3.5

H₂O = 3.5-2.1 = 1.4 >> polar

• O₂

= 3.5-3.5 = 0 >> non polar