Question

An atom has 8 protons, 9 Neutrons, and 10 electrons. What is the mass number?

Answer 1

The mass number of an atom is the sum of its protons and neutrons. For an atom with 8 protons and 9 neutrons, the mass number is 17.

Step-by-step explanation:

The mass number of an atom, often symbolized as A, is defined as the total number of protons and neutrons in the nucleus of that atom. The mass number is calculated using the formula A = (number of protons) + (number of neutrons). For an atom with 8 protons, 9 neutrons, and 10 electrons, the mass number is 17 (8 protons + 9 neutrons). Electrons are not included in the mass number calculation because they have a very small mass compared to protons and neutrons.

Answer 2

17

Step-by-step explanation:

Mass number = # of protons + # of neutrons

Mass number is calculated using ONLY protons and neutrons. Electrons are not in the count.

Thus, we simply add them together: 8 + 9 = 17

This element is Oxygen - 17.