Question

X is an element with the atomic number 20. Find whether X is more or less reactive than Mg.

Answer 1

Solution:

Magnesium:

• Magnesium is an alkaline earth metal.
• It is the ninth most common element on the planet.
• Magnesium atoms have $12$ protons and $12$ electrons.

According to the question:

• The electronic configuration of the element X with atomic number $\left(20\right)$ will be $2,8,8,2$.
• The electronic configuration of$\mathrm{Mg}$is $2,8,2$.
• $\mathrm{Mg}$has three shells and ‘X’ has four shells.
• The more the number of shells of an atom, the greater is the distance between the nucleus and the outermost electrons.
• A decrease in the effective nuclear charge is experienced making it easier to lose electrons due to decreasing forces of attraction.
• Thus, the element becomes more reactive with an increase in atomic size.

Thus, element X is greater in atomic size than$\mathrm{Mg}$.

Therefore, Element X is more reactive than$\mathrm{Mg}.$