Question

A scientist is trying to determine the identity of an element. It is highly reactive to water and forms an ionic bond with chlorine. It is also very shiny. The element is likely A. from Group 17. B. from Group 1. C. from Group 15. D. a noble gas.

Answer 1

The answer is noble gas. Since noble gas are constant and unreactive. They can still shape compounds with other elements. 
Group 15 is also group 5A and Group 17 is also group 7A. Elements in these sets do not typically form ionic bonds; they are more on creating covalent bonds since they're non-metals. 
Therefore, that leaves us with B. from Group 1. They are metals (but Hydrogen) which respond violently with water, and they form ionic bonds, for they drop outer electrons easily.