Sodium iodide (NaI) is an ionic compound because when the metal combines with nonmetal, it usually forms an ionic compound. Here, Na (sodium) is a metal and I (iodine) is a nonmetal. So when they combine, it forms an ionic compound.
Well, now you have got to know that NaI is an ionic compound, but let me explain the in-depth reason why NaI is an ionic compound.
Why is NaI an ionic compound?
As mentioned above, you can simply remember that when the metal combines with nonmetal, the bond between them is an ionic bond.
Here in NaI, the Na atom is a metal and the I atom is a nonmetal.
Hence the bond between them is an ionic bond.
How does the ionic bond form between Na and I?
In NaI, there are two atoms;
Na and I.
About Sodium (Na):
Sodium atom have 11 electrons.
The electrons arrangement in Sodium (Na) is 2, 8, 1.
So the outermost orbit of Sodium atom has 1 electron.
Now Sodium is a metal and the metals are highly electropositive (that means they have the tendency to lose electrons and become positive ions.)
Hence during the chemical reaction, the Sodium atom will lose 1 electron to form a stable octet.
About Iodine (I):
Iodine atom have 53 electrons.
The electrons arrangement in Iodine (I) is 2, 8, 18, 18, 7.
So the outermost orbit of an Iodine atom has 7 electrons.
Now Iodine is a nonmetal and the nonmetals are highly electronegative (that means they have the tendency to gain electrons and become negative ions.)
Hence during the chemical reaction, the Iodine atom will gain 1 electron to form a stable octet.
What happens when Na and I combine?
When Na and I combine with each other, the electron transfer takes place from Sodium atom to Iodine atom (i.e from Na to I).
In other words, the Sodium atom (Na) loses 1 electron and the Iodine atom (I) gains 1 electron.
Due to this, the Sodium becomes a positive ion (Na+) and Iodine becomes a negative ion (I–).
Now because of the positive charge of Sodium ion and negative charge of Iodine ion, the electrostatic force of attraction is produced between them.
This electrostatic force between Sodium ion and Iodine ion results in an ionic bond between them.
Hence, NaI is an ionic compound.
I hope you have understood the reason why NaI is an ionic compound.
Check out other compounds to see whether they are ionic or covalent;
Is CsF Ionic or Covalent?
Is KF Ionic or Covalent?
Is KOH Ionic or Covalent?
Is PF3 Ionic or Covalent?
Is PBr3 Ionic or Covalent?
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online learning platform that provides students with easily understandable explanations.
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