What sort of bonding exists in the salt formed between strontium metal and iodine?

2 Answers
Feb 8, 2017

Strontium Iodide #SrI_2# has ionic bonding


Strontium being in family II A has two valance electrons that it can "share" with other atoms.

Iodine being in family VII A has seven valance electrons it needs one more electron to achieve the stable structure of an inert gas.

The ratio of the two atoms is then 1:2. It takes two iodine atoms to "share" with the two valance electrons of one strontium atom. This gives the chemical formula of #SrI_2#

Strontium like all the alkali earth metals has a low electronegativity. This means that Strontium has a very weak pull for electrons. While Iodine being in the halogen family has a very strong pull for electrons. This causes the "shared" electrons in the bond to be pulled much more strongly toward the Iodine atom than strontium atom. This results in an ionic bond.

Feb 8, 2017

#"Strontium iodide, "SrI_2#, is an ionic solid....


Strontium is an alkaline earth metal that forms #Sr^(2+)# ions. Iodine is an halogen that forms #I^-# ions...........

And we could represent the formation of the ionic compound as:

#Sr + I_2 rarr SrI_2#

Is this a redox reaction?