August 17, 2022 Chemistry Regent Exam
1. What is the number of protons in an atom with the electron configuration of 2-5?
(1) 5
(2) 2
(3) 3
(4) 7
Explanation: Refer to the Periodic Table on the Reference Tables for Physical Setting/CHEMISTRY.
Every element has at the bottom. Nitrogen has a 2-5 electron configuration on the Periodic Table. The number of protons in an atom is equal to the atomic number which is the bottom left corner. The atomic number is equal to 7. Alternatively, the number of electrons is equal to the number of protons in a neutral atom. So we can just add 2+5 = 7
Answer: 4 is the correct answer.