Atoms of which element react spontaneously with mg2+ (aq)?

The complete answer contains the answer choices.

This is the complete question:

Atoms of which element react spontaneously with Mg2+(aq)? (1)chromium
(2)barium
(3)iron
(4)zinc

option 2. barium.

Explanation.

1) Mg ²⁺ (aq) is the aquous cation of the metal Mg.

2) Only a metal more reactive than Mg will be able to exchange with it the oxidation states.

3) Mg is an earth alkalyne metal (group 2 of the periodic table). The metals from this group are more reactive than the metals in the groups to its right: 3, 4, 5, 6, 7, ... Only the alkalyne metals (those in group 1) are more reactive than the earth alkalyne metals.

4) Of the list, barium is the only alkalyne metal, so it is more reactive than Mg and will be able to deliver 2 electrons to transform the cations Mg²⁺ into Mg while the very Ba will become Ba²⁺.

5) Chromium, iron and zinc are transition metals, so less metallic (reactive) than Mg.

257 grams h2o i think