Question

strontium chloride is an ionic compound. it is used in fireworks to produce red light. which lewis structure correctly represents strontium chloride? choose 1 answer: ① $cdotmathrm{sr}cdot^{2 - }colonddot{mathrm{cl}}cdot^{+}cdotmathrm{sr}cdot^{2 - }$ ② $mathrm{sr}^{2+}colonddot{mathrm{cl}}colon^{-}mathrm{sr}^{2+}$ ③ $colonddot{mathrm{cl}}cdot^{+}cdotmathrm{sr}cdot^{2 - }colonddot{mathrm{cl}}cdot^{+}$ ④ $colonddot{mathrm{cl}}colon^{-}mathrm{sr}^{2+}colonddot{mathrm{cl}}colon^{-}$

Explanation:

Step1: Analyze strontium and chlorine ions

Strontium (Sr) is in group 2 of the periodic table and loses 2 electrons to form a $Sr^{2 +}$ ion. Chlorine (Cl) is in group 17 and gains 1 electron to form a $Cl^{-}$ ion.

Step2: Determine correct Lewis - structure

In strontium chloride ($SrCl_{2}$), one $Sr^{2+}$ ion is surrounded by two $Cl^{-}$ ions. The correct Lewis - structure has a $Sr^{2+}$ ion and two $[Cl:]^{-}$ ions.

Answer:

D. $[\ddot{Cl}:]^{-}[Sr]^{2 +}[\ddot{Cl}:]^{-}$