An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?(1 point)
Responses
58
58
19
19
20
20
39
To determine the mass number of an atom, you need to add the number of protons and neutrons together. The number of protons is given as 19 and the number of neutrons is given as 20. Adding these two numbers gives us:
19 + 20 = 39
Therefore, the mass number of the atom is 39.
The mass number of an atom is equal to the sum of its protons and neutrons. Given that the atom has 19 protons and 20 neutrons, the mass number can be calculated as follows:
Mass number = number of protons + number of neutrons
Mass number = 19 + 20
Mass number = 39
Therefore, the mass number of the atom is 39.