Question

Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will they form between them and why?

Answer 1

All elements are composed of a subatomic particle of electrons and protons. The atomic number is the total number of protons present in the element. Generally in neutral atoms, the number of electrons and protons is usually the same. According to the atomic number the elements are placed in the modern periodic table.

Complete step by step answer:
The modern version of the periodic table called the modern periodic table is the most conventionally and widely used. The horizontal rows are called periods and the vertical columns are called groups. The elements with a similar electronic configuration in the outer shell of the atoms are arranged in vertical columns called groups and families.
The principal quantum number defines the main energy level of the shell, these shells can be further divided into subshells namely s, p, d, etc. The distribution of electrons in the last orbital reflects the position of the element in the periodic table
The period indicates the value of n for the outermost or valence shell.
Here the given atomic numbers are 12 and 16, writing the electronic configuration of these elements we get,

$2 \Rightarrow 1{s^2}2{s^2}2{p^6}3{s^1}$

$16 \Rightarrow 1{s^2}2{s^2}2{p^6}3{s^2}3{p^4}$

Since the last electrons go in the third shell so they must belong to the third period.
Upon analysis, we find that the atomic numbers 12 and 16 belong to magnesium and sulfur respectively. Magnesium being the metal will tend to lose an electron to gain stability in the ionic state while the sulfur atom being a non-metal tends to gain electrons for stability.
So the electrons of the valence or the outermost orbital which will be donated by magnesium will be accepted by the sulfur atom to form an ionic bond. The ionic bond is the bond that is characterized by the transfer of electrons from one atom to another for the formation of the bond.

Note: The atomic number of the atom is the total number of protons present in the nucleus of the atom. The total number of the electrons is not a reliable measure for the atomic number as the number of electrons can vary as the atom tends to lose or gain electrons based on their bonding needs.

The modern periodic table is formed based on the plot of modern periodic law which states that the physical and chemical properties of the elements are a function of their atomic number.