Which statement best explains why hydrogen’s atomic number is equal to its mass?(1 point)

Question

Responses

Hydrogen only has one electron
Hydrogen only has one electron

Hydrogen is stable, with two electrons in its outer shell.
Hydrogen is stable, with two electrons in its outer shell.

Hydrogen is in the first row and the first column of the periodic table.
Hydrogen is in the first row and the first column of the periodic table.

Hydrogen does not have any neutrons.
Hydrogen does not have any neutrons.

Answer 1

The statement that best explains why hydrogen’s atomic number is equal to its mass is:

Hydrogen does not have any neutrons.

Hydrogen has an atomic number of 1, which means it has one proton and typically one electron. The most common isotope of hydrogen (protium) has no neutrons, so its atomic mass is very close to 1 (specifically about 1.008 amu). Thus, the atomic number (number of protons) and the mass (for this isotope) reflect the absence of neutrons.