What does the atomic mass show?
Group of answer choices
number of protons
number of protons + electrons
number of protons + neutrons
number of electrons
The atomic mass shows the number of protons + neutrons in an atom.
The atomic mass of an element represents the total mass of one atom of that element. It is typically expressed in atomic mass units (amu). The correct answer is: the number of protons + neutrons.
To find the atomic mass of an element, you need to know the number of protons (which is equal to the atomic number) and the number of neutrons in the nucleus of an atom. The number of electrons does not contribute significantly to the atomic mass because their mass is much smaller compared to protons and neutrons.
To get the atomic mass of an element:
1. Identify the element and find its atomic number on the periodic table. The atomic number represents the number of protons in the nucleus.
2. Look for the atomic mass (sometimes called the atomic weight) beneath or above the element symbol on the periodic table.
3. The atomic mass is a decimal number because it takes into account the average mass of the different isotopes of the element, which have different numbers of neutrons. It is usually presented in the form of a weighted average.
4. The atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom.
So, the correct answer is the number of protons + neutrons when referring to the atomic mass.