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

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

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

Example

H = 2.1

O = 3.5

H₂O = 3.5-2.1 = 1.4 >> polar

= 3.5-3.5 = 0 >> non polar

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g