K2S is an ionic compound because when the metal combines with nonmetal, it usually forms an ionic compound. Here, K is a metal and S is a nonmetal. So when they combine, it forms an ionic compound.
Well, now you have got to know that K2S is an ionic compound, but let me explain the in-depth reason why K2S is an ionic compound.
If you are a visual learner like me, then here is a short one minute video for you.
Why is K2S 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 K2S, the K atom is a metal and the S atom is a nonmetal.
Hence the bond between them is an ionic bond.
How does the ionic bond form between K and S?
In K2S, there are two atoms;
K and S.
About Potassium (K):
Potassium atom have 19 electrons.
The electrons arrangement in Potassium (K) is 2, 8, 8, 1.
So the outermost orbit of Potassium atom has 1 electron.
Now Potassium 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 Potassium atom will lose 1 electron to form a stable octet.
About Sulfur (S):
Sulfur atom have 16 electrons.
The electrons arrangement in Sulfur (S) is 2, 8, 6.
So the outermost orbit of Sulfur atom has 6 electrons.
Now Sulfur 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 Sulfur atom will gain 2 electrons to form a stable octet.
What happens when K and S combine?
When K and S combine with each other, the electron transfer takes place from Potassium atom to Sulfur atom (i.e from K to S).
In other words, each Potassium atom (K) loses 1-1 electrons and the Sulfur atom (S) gains 2 electrons.
Due to this, Potassium becomes a positive ion (K+) and Sulfur becomes a negative ion (S2-).
Now because of the positive charge of Potassium ion and negative charge of Sulfur ion, the electrostatic force of attraction is produced between them.
This electrostatic force between Potassium ion and Sulfur ion results in an ionic bond between them.
Hence, K2S is an ionic compound.
I hope you have understood the reason why K2S is an ionic compound.
Check out other compounds to see whether they are ionic or covalent;
Is SF4 Ionic or Covalent?
Is Br2 Ionic or Covalent?
Is K3PO4 Ionic or Covalent?
Is CsCl Ionic or Covalent?
Is KNO3 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.
Read more about our Editorial process.
