Question

Elements are organized on the periodic table based on their properties. Which statement correctly predicts and explains the chemical reactivity of two metals?
A) The alkali metal atom forms a +1 ion, while the alkaline earth metal atom forms a +2 ion.
B) The alkali metal atom forms a +2 ion, while the alkaline earth metal atom forms a +1 ion.
C) The alkali metal atom has one less shell of electrons than the atom of the alkaline earth metal.
D) The alkali metal atom has one more shell of electrons than the atom of the alkaline earth metal.

Answer 1

Answer: The correct answer is Option A.

Explanation:

Chemical reactivity is defined as the tendency of an atom to loose or gain electrons.

Metals are the elements that looses electrons and thus, their chemical reactivity will be the tendency to loose electrons.

Their chemical reactivity decreases as we move from left to right in a period. This is so because, the electron get added up in the same shell. So, the electron in the outermost orbital gets more tightly bonded to nucleus. And hence, loosing an electron will require high energy. Thus, the chemical reactivity decreases.

• Alkali metals are the elements which belong to group 1 of the periodic table. The general electronic configuration of these metals is $ns^1$

These metals will loose 1 electron to form +1 ions.

• Alkaline earth metals are the elements which belong to group 2 of the periodic table. The general electronic configuration of these metals is $ns^2$

These metals will loose 2 electrons to form +2 ions.

Hence, the correct answer is Option A.

Answer 2

A) The alkali metal atoms forms a +1 ion, while the alkaline eaeth metal atom forms a +2 ion.