Answer:
c. 6.
Explanation:
Looking at the description given in the question, the elements involved must belong to the p- block of the periodic table and must be in period 5. They also must possess valence electrons in the 5p- orbital.
Now if we look at the p- block of period 5, the following elements satisfy these  requirements; Sr, In, Sn, Sb, Te and I.
Hence there are six of such elements.
The chemical elements that have atoms, in their ground-state, with valence electrons whose quantum numbers are n = 5 and l = 1 are: C. 6.
A valence electron can be defined as the number of electrons that is present in the outermost shell of an atom.
In Chemistry, valence electrons are primarily used to determine whether an atom or group of chemical elements that are found on the periodic table can bond with others.
Based on electronic configuration, quantum numbers of n = 5 and l = 1 simply represents a 6p orbital and there a total of six (6) chemical elements with this orbital, and these include;
Read more on valence electrons here: https://brainly.com/question/16554158
