Which of the following pairs of 'number - composition' is correct?
I. Atomic number - number of protons
II. Mas number - Sum of number of neutrons and protons
Answer & explanation
Correct answer: option 3
The correct answer is option 3. Both I and II.
The correct pair of 'number - composition' is Both I and II
I. Atomic Number: The atomic number is indeed the number of protons in an atom. It uniquely identifies an element and determines its position in the periodic table.
II. Mass Number: The mass number is the sum of the number of protons and neutrons in the nucleus of an atom. It represents the total nucleons (protons + neutrons) in an atom.