Question

an atom has an atomic number of 15 and a mass number of 31. how many protons are there in the atom? 15 31 16 47 which element is found in group 16 period 3? * sulfur (s) selenium (se) chlorine (cl) carbon (c)

Explanation:

• For the first question: The atomic number of an atom is equal to the number of protons in its nucleus. Given the atomic number is 15, so the number of protons is 15.
• For the second question: Sulfur (S) is in group 16 (also known as the oxygen - family or chalcogens) and period 3 of the periodic table. Selenium (Se) is in period 4, chlorine (Cl) is in group 17, and carbon (C) is in group 14.

Answer:

15
Sulfur (S)