An atom with 4 protons, 5 neutrons, and 4 electrons has an atomic mass of _ amu. (Enter a whole number.) Numerical Answers Expected! Answer for Blank 1:
The Correct Answer and Explanation is:
Correct Answer for Blank 1: 9
Explanation:
The atomic mass of an atom is the sum of the masses of its protons and neutrons. Electrons have a negligible mass compared to protons and neutrons, so their mass is usually not considered in the calculation of atomic mass.
Here is how you calculate it:
- Number of protons = 4
Each proton has a mass of approximately 1 amu - Number of neutrons = 5
Each neutron has a mass of approximately 1 amu - Number of electrons = 4
Electrons have very little mass (about 1/1836 of a proton)
So, for atomic mass calculations, the mass of electrons is usually ignored
Atomic Mass Calculation:
Atomic Mass = Number of Protons + Number of Neutrons
Atomic Mass = 4 + 5 = 9 amu
Thus, the atomic mass of this atom is 9 amu.
Additional Notes:
- The atom with 4 protons is Beryllium (Be)
- The number of protons defines the element’s identity
- The number of neutrons can vary, leading to different isotopes of the same element
- This particular isotope of Beryllium has 5 neutrons, making it an isotope with an atomic mass of 9 amu
Beryllium-9 is the most common and stable isotope of Beryllium found in nature. The atom is neutral since it has equal numbers of protons and electrons (4 each), meaning no overall electrical charge.
In summary, atomic mass focuses on the mass of the nucleus which consists of protons and neutrons, resulting in a total atomic mass of 9 amu for this atom.
