Ionic bonds are formed when there is complete transfer of valence electrons between two atoms.
Electronegativity tells the trend of an atom to atract electrons.
You should search for the complete set of rules that indicate whether an ionic or covalent bond happens.
There are two relevant rules to state if whether an ionic bond will happen:
- When the difference of electronegativities between the two atoms is greater than 2.0, then the bond is ionic.
- When the difference is between 1.6 and 2.0, the bond is ionic if one of the elements is a metal.
You need to list the electronegativities of the five elements (there are tables with this information)
Element electronegativity
Cu: 1.9
H: 2.2
Cl 3.16
I: 2.66
S: 2.58
Differences:
Cu / S: 2.58 - 1.9 = 0.68
H / S: 2.58 - 2.2 = 0.38
Cl / S: 3.16 - 2.58 =0.58
I / S: 2.66 - 2.58 = 0.08
Those differences are too low to consider that the bond is ionic.
Then the answer is that none of those atoms forms an ionic bond with sulfur.
An ionic bond is composed of a cation and anion, which are charged ions. You cannot have atoms with ionic bonds, because there is no opposite attraction between charges due to atoms having a net nuclear charge of zero. Therefore, a cation and anion would most likely be joined by an ionic bond.
... and a power ot ten.
For example: 1,3x10^21 is in scientific notation, but 13x10^20 is not in scientific notation.