Help asap! Which statement concerning MgBr2 is true?
A. MgBr2 has properties similar to sodium metal and chlorine gas.
B. MgBr2 is a homogeneous mixture.
C. MgBr2 is a heterogeneous mixture.
D. The percentage of Mg in MgBr2 is dependent on where the sample is obtained.
E. MgBr2 is a compound composed of Magnesium and Bromine

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.