What is the mass number of an atom of potassium that has 20 neutrons?
mass # = # protons + # neutrons.
Atomic number = # protons.
39
What is the charge of potassium atom if you substract the number of electrons and the number of protons?
To find the mass number of an atom of potassium with 20 neutrons, we need to understand the concept of the atomic structure.
The atomic structure of an atom includes protons, neutrons, and electrons. The protons and neutrons are present in the nucleus of the atom, while electrons orbit around the nucleus.
The mass number represents the total number of protons and neutrons in the nucleus of an atom. Since neutrons have no charge, they do not significantly affect the chemical properties of an element but do contribute to its mass.
In the case of potassium, its atomic number is 19, which means it has 19 protons in its nucleus, giving it a partial positive charge.
The mass number is calculated by adding the number of protons and neutrons. Knowing that an atom of potassium with 20 neutrons is desired, we can calculate the mass number as follows:
Mass number = Number of protons + Number of neutrons
Mass number = 19 protons + 20 neutrons
Mass number = 39
Therefore, the mass number of an atom of potassium with 20 neutrons is 39.