The atom that fits these criteria is Chromium-54 (⁵⁴Cr).
Understanding Atomic Composition
Every atom is defined by its unique atomic composition, specifically the number of protons it contains. Protons are positively charged particles located in the nucleus of an atom.
- Protons (p+): The number of protons determines an atom's atomic number (Z) and, consequently, its chemical identity—what element it is. Each element has a unique, fixed number of protons.
- Neutrons (n⁰): Neutrons are neutral particles also found in the nucleus. While they contribute significantly to an atom's mass, they do not affect its elemental identity. Atoms of the same element can have different numbers of neutrons, leading to different isotopes.
- Mass Number: The mass number represents the total count of protons and neutrons in an atom's nucleus. It is essentially the approximate atomic mass in atomic mass units (amu).
Identifying the Element
The question specifies that the atom contains 24 protons. According to the fundamental principles of chemistry, the number of protons (atomic number, Z) uniquely identifies an element. An element with an atomic number of 24 is Chromium.
- Atomic Number (Z) = 24
- Element = Chromium (Cr)
This means any atom with 24 protons is, by definition, an atom of Chromium. You can learn more about Chromium and its properties on the Royal Society of Chemistry Periodic Table.
Determining the Isotope
Beyond the element's identity, the question also provides the mass number, which is 54. The mass number is the sum of protons and neutrons. We can use this information to determine the number of neutrons and thus the specific isotope:
- Mass Number = Number of Protons + Number of Neutrons
- 54 = 24 + Number of Neutrons
By rearranging the equation, we can find the number of neutrons:
- Number of Neutrons = Mass Number - Number of Protons
- Number of Neutrons = 54 - 24 = 30
Therefore, this specific atom of chromium contains 30 neutrons. An isotope is named by its element followed by its mass number. In this case, it is Chromium-54. Its isotopic symbol is often written as ⁵⁴Cr.
Key Characteristics of Chromium-54
Chromium-54 is a stable isotope of chromium, distinguished by its particular atomic composition.
| Characteristic | Value |
|---|---|
| Element Name | Chromium |
| Chemical Symbol | Cr |
| Atomic Number (Z) | 24 |
| Number of Protons | 24 |
| Number of Neutrons | 30 |
| Mass Number | 54 |
| Isotope Notation | Chromium-54 (⁵⁴Cr) |
This combination of 24 protons and 30 neutrons gives it a mass number of 54, precisely matching the description.
