Beryllium has an atomic number of 4 and an atomic mass of approximately 9. How many protons does a beryllium atom have?
The correct answer and explanation is:
A beryllium atom has 4 protons. This is because the number of protons in an atom is defined by its atomic number, and for beryllium, the atomic number is 4. The atomic number indicates the number of protons in the nucleus of an atom, and since beryllium’s atomic number is 4, it must have exactly 4 protons.
Protons are subatomic particles found in the nucleus of an atom, and they carry a positive charge. The number of protons in an atom determines its chemical identity and its place in the periodic table. Every element on the periodic table has a unique number of protons, which is represented by its atomic number. For instance, hydrogen has 1 proton, helium has 2, and so on. Because of the number of protons, each element reacts differently in chemical reactions.
The atomic mass of beryllium, approximately 9, is the sum of the protons and neutrons in its nucleus. Beryllium has 4 protons, so the remaining particles in its nucleus must be neutrons. To calculate the number of neutrons, subtract the number of protons from the atomic mass. Since beryllium’s atomic mass is 9, the number of neutrons is 9 – 4 = 5. This means that in a typical beryllium atom, there are 5 neutrons.
The relationship between protons, neutrons, and electrons in an atom is essential for understanding the element’s behavior in chemical reactions and its isotopes. Beryllium’s 4 protons also ensure that it has 4 electrons in a neutral atom, balancing the positive charge of the protons with the negative charge of the electrons.