Question

Given the isotope name potassium-57.Find the atomic number, mass number, number of protons, number of electrons, and number of neutrons in it.

Answer 1

• As we know that potassium is the 19^th element in the periodic table since its atomic number is 19.
• The number of protons and atomic number are the same hence, the number of protons=19.
• A neutral atom has an equal number of protons and electrons since the atom is electrically neutral. Thus the number of electrons=19.
• The mass number is given as 57.
• Mass number=sum of a number of protons and neutrons.
• Thus number of neutrons=mass number -number of protons=(57-19)=38.
• atomic number=19, mass number=57, number of protons=19, number of electrons=19, number of neutrons=38.