Question

Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table?
A) Group 8
B) Group 2
C) Group 18
D) Group 10

Answer 1

Hint: Determine the number of valence electrons. From the number of valence electrons, identify the group number.

Complete answer:
Group 2 elements contain 2 valence electrons. Group 10 elements contain 2 electrons in s subshell and 8 electrons in penultimate d subshell. The first element is group 10 is nickel with an atomic number of 28.
The electronic configuration of the element is 2,8. It has a total of 10 electrons. So, the atomic number is 10. The element is neon, an inert gas or noble group element. In the electronic configuration 2,8 the octet is complete as the valence shell is having 8 electrons. This suggests a noble gas element. In the modern periodic table, noble gas elements are present in the group 18.
Hence, you would locate the element with electronic configuration 2, 8 in the Modern Periodic Table in the group 18.

Hence, the option (C) is the correct option.

Additional Information: The elements present in group 18 are helium, neon, argon, krypton, xenon and radon.

Note: Do not write that the group number is 8 as there are 8 valence electrons. The group 8 contains transition metals in which the penultimate d subshell is also filled. The first element is group 8 is iron with atomic number of 26.