Question

question 22 (1 point) saved
an elements atomic number is identical to the number of:
a) protons and neutrons it has
b) protons and electrons it has
c) its mass
d) electrons it has but not protons
e) electrons and neutrons it has

Explanation:

The atomic number of an element is defined as the number of protons in the nucleus of an atom of that element. In a neutral atom, the number of electrons is equal to the number of protons. So, the atomic number is identical to the number of protons (and in a neutral state, also electrons).

• Option a: Protons + neutrons = mass number (not atomic number).
• Option b: Correct as atomic number = number of protons (and in neutral atoms, electrons too).
• Option c: Mass is different from atomic number.
• Option d: Incorrect as atomic number is based on protons (and in neutral atoms, electrons).
• Option e: Electrons + neutrons has no direct relation to atomic number.

Answer:

B. protons and electrons it has