Ionic vs. Covalent Compounds

[Amanda Bueno-Kling]

Can anyone explain why NaCl is an ionic compound and HCl is a molecular compound? Can we figure this out just by looking at the periodic table?

[Morgan Gee 3B]

A general rule of thumb is that covalent molecules are two nonmetals bonded and ionic compounds are a nonmetal and a metal bonded together. While H is on the left side of the table, it is still considered a nonmetal (think H2 gas). This explains why NaCl (a metal and nonmetal) is ionically bonded while HCl (two nonemtals) is covalently bonded.

[Victor Li 2A]

Ionic compounds are usually formed between a nonmental (very electronegative) and a metal (low ionization energy). Meanwhile, covalent molecules are formed between two nonmetals (both very electronegative) so elections are shared. Looking at the periodic table, elements located near the lower-left corner have very low ionization energies, and elements located near the top right corner (not noble gases) have very high electronegativities. So based on the elements' locations in the periodic table, you can generally figure out whether a bond is covalent or ionic.

[Francesca_Borchardt_2D]

I was having trouble understanding this as well. Thank you all for explaining it so well, it really helped.

[Lung Sheng Liang 3J]

Ionic bonds are when a metal and a nonmetal make a compound. This means that the nonmetal usually takes the electron from the nonmetal. Covalent compounds are when both atoms share the electron(s), in most cases, between two nonmetals.

[simona_krasnegor_1C]

I usually go off the fact that ionic compounds involve one metal and one nonmetal, while covalent compounds involve two nonmetals.

[Sarah Salam 1J]

Ionic bonds are formed by nonmetals and metals, since metals usually have few valence electrons, they will give their electrons to nonmetals. Covalent bonds are when an electron is being shared between two atoms, usually these are nonmetals.

[Megan ODonnell 3F]

NaCl is ionic because it has a great enough difference in electronegativities between the metal and non metal, whereas HCl doesn't have a large enough difference in electronegativities for the Cl to take the electron from H. Usually, a metal and a nonmetal form an ionic bond, and two nonmetals form a covalent bond.