An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?(1 point)
39
39
19
19
20
20
58
The mass number of an atom is the sum of its protons and neutrons. In this case, the atom has 19 protons and 20 neutrons, so the mass number is 19 + 20 = 39.
To find the mass number of an atom, you need to add the number of protons and neutrons. In this case, the atomic model shows 19 protons and 20 neutrons. Adding these numbers together gives a mass number of 39.
To find the mass number of an atom, you need to add up the number of protons and neutrons. Protons and neutrons contribute to the mass of an atom, while electrons have negligible mass.
In this case, the atomic model shows 19 protons and 20 neutrons. To find the mass number, simply add these two numbers together:
19 protons + 20 neutrons = 39
Therefore, the mass number of the atom is 39.