Chromium, calcium, and potassium are near each other on the periodic table and have some common characteristics but differ in chemical reactivity. Which lists these metals in order from most reactive to least reactive?

Answer : The reactivity order from most reactive to least reactive will be:

Potassium > Calcium > Chromium

Explanation:

Chemical reactivity : It is defined as the tendency of an element to loose or gain electrons.

Metals are the elements which loose electrons and hence, their chemical reactivity will be the tendency to loose electrons.

Their chemical reactivity decreases as we move from left to right in a period because the valence shell come closer to nucleus as we move from left to right. So, tendency to loose electrons becomes difficult due to greater attraction between nucleus and valence electron.

Thus, the reactivity order from most reactive to least reactive will be:

Potassium > Calcium > Chromium

Potassium>Calcium>Chromium

Explanation:

Potassium belongs to alkali metals which are most reactive in the periodic table.

As we move from left to right reactivity of elements decreases because the atomic number increases and the outer shell become more full so electron affinity becomes less.