In the long form of the periodic table, the valence shell electronic configuration of $$5s^25p^4$$ corresponds to the element present in:

The valence shell electronic configuration given is $$5s^2 5p^4$$. To determine the group and period of this element in the long form of the periodic table, we analyze the valence electrons and the principal quantum number.

The period number is determined by the highest principal quantum number in the valence shell. Here, the valence shell has electrons in the 5s and 5p orbitals, so the highest principal quantum number is 5. Therefore, the element is in period 5.

The group number is determined by the total number of electrons in the valence shell. The valence shell includes the s and p orbitals of the highest principal quantum number. The configuration $$5s^2 5p^4$$ indicates:

• 2 electrons in the s orbital
• 4 electrons in the p orbital

Adding these together: $$2 + 4 = 6$$. So, there are 6 valence electrons.

In the p-block of the periodic table (groups 13 to 18), the group number corresponds to the total number of valence electrons. Specifically:

• ns² np¹ corresponds to group 13
• ns² np² corresponds to group 14
• ns² np³ corresponds to group 15
• ns² np⁴ corresponds to group 16
• ns² np⁵ corresponds to group 17
• ns² np⁶ corresponds to group 18

Since the configuration is $$5s^2 5p^4$$, it matches ns² np⁴, which belongs to group 16.

Therefore, the element is in group 16 and period 5.

Now, comparing with the options:

• A. Group 16 and period 5
• B. Group 17 and period 5
• C. Group 16 and period 6
• D. Group 17 and period 6

Hence, the correct answer is Option A.