Understanding the Basics
* Atomic Mass: The atomic mass of an atom is the average mass of all its isotopes (atoms of the same element with different numbers of neutrons).
* Atomic Number: The atomic number of an element is the number of protons in its nucleus. It's also the element's position on the periodic table.
* Neutrons: Neutrons are neutral particles found in the nucleus of an atom.
Steps
1. Find the atomic number of potassium (K): Look up potassium on the periodic table. Its atomic number is 19. This means it has 19 protons.
2. Calculate the number of neutrons:
* Atomic mass ≈ Number of protons + Number of neutrons
* 39 amu ≈ 19 + Number of neutrons
* Number of neutrons ≈ 39 - 19 = 20
Answer: A potassium atom with an atomic mass of 39 amu has approximately 20 neutrons in its nucleus.
