Question

Elements 'X' and 'Y' have their electronic configuration as $x,x^3,x^3–1$ and $x,x^3,x^2–3$. Which of the following is correct for elements 'X' and 'Y'?

• A. Both the elements are metallic
• B. Both the elements are inert
• C. Both the elements belong to same group
• D. Both the elements belong to same period

Answer 1

The correct option is D Both the elements belong to same period

The first shell of any atom can have a maximum number of two electrons. Thus, x is equal to 2.
The electronic configuration of element ‘X’ is $2,2^3,2^3–1$, i.e. 2, 8, 7. Since it has seven valence electrons, it belongs to group 17. It will gain one electron to complete its octet and therefore, it is a non-metal.
The electronic configuration of element ‘Y’ is $2,2^3,2^2–3$, i.e. 2, 8, 1. Since it has one valence electron, it belongs to group 1. It will lose one electron to achieve noble gas configuration and therefore, it is a metal.
Both X and Y have three filled shells and thus, belong to period 3 of the periodic table.
Hence, the correct answer is option (d).