The Continuum of Chemical Bonding (Leaving Cert Chemistry): Flashcards

Basis of bonding continuum

Electronegativity difference

Electronegativity difference scale range

0 to 3.2

Pure covalent: electronegativity difference

0 to 0.4

Polar covalent: electronegativity difference

0.4 to <1.7

Ionic bond: electronegativity difference

1.7

Threshold for polar vs nonpolar

0.4

Threshold for covalent vs ionic

1.7

Partial charges in polar covalent bonds

$\delta^-$ and $\delta^+$

Rule: electronegativity difference >1.7

Ionic bonding

Rule: electronegativity difference $\leq 1.7$

Covalent bonding

Metal hydrides bonding exception

Ionic despite rule suggesting covalent

HF bonding type (difference 1.78)

Covalent (exception to rule)

$\text{BeF}_2$ bonding type (difference 1.94)

Covalent (exception to rule)

Pure covalent: exact electronegativity difference

0 (nonpolar)