The isotope containing 56 protons, 54 electrons, and 74 neutrons is Barium-130 ion (Ba$^{2+}$). This specific isotope is recognized as barium 130, and its ionic form arises from the difference in proton and electron counts.
Unpacking the Isotope's Identity
To determine the identity of an isotope, we rely on the fundamental properties defined by its subatomic particles: protons, neutrons, and electrons.
1. Determining the Element
The number of protons uniquely identifies an element.
- In this case, with 56 protons, the element is Barium (Ba). Each element on the periodic table is defined by its atomic number, which is equal to the number of protons in its nucleus. You can verify this on a periodic table of elements.
2. Calculating the Mass Number
The mass number (A) of an isotope is the sum of its protons and neutrons. This number represents the total nucleons (particles in the nucleus).
- Protons: 56
- Neutrons: 74
- Mass Number = Protons + Neutrons = 56 + 74 = 130
- Therefore, this is an isotope of Barium with a mass number of 130, commonly written as Barium-130 or $^{130}$Ba.
3. Identifying the Charge
The charge of an atom or ion is determined by the balance between its protons (positive charge) and electrons (negative charge).
- Protons: 56 (+)
- Electrons: 54 (-)
- Net Charge = Protons - Electrons = 56 - 54 = +2
- Since the number of protons exceeds the number of electrons, the species carries a net positive charge, forming a cation. In this case, it's a Barium ion with a +2 charge, written as Ba$^{2+}$.
Summary of Isotope Properties
The following table summarizes the properties of this specific isotope:
| Property | Value | Explanation |
|---|---|---|
| Number of Protons | 56 | Defines the element as Barium (Ba). |
| Number of Neutrons | 74 | Contributes to the mass number, indicating an isotope of Barium. |
| Number of Electrons | 54 | Fewer electrons than protons result in a positive ionic charge. |
| Atomic Number (Z) | 56 | The number of protons. |
| Mass Number (A) | 130 | Protons (56) + Neutrons (74). |
| Element Identity | Barium (Ba) | Determined solely by the atomic number (number of protons). |
| Ionic Charge | +2 | (Protons - Electrons) = 56 - 54. |
| Isotope Identity | $^{130}$Ba$^{2+}$ | The full identity, including mass number and ionic charge. |
Why Barium-130?
Barium is an alkaline earth metal, typically forming +2 ions by losing its two valence electrons to achieve a stable electron configuration. Barium-130 is one of the naturally occurring isotopes of barium. Understanding the number of protons, neutrons, and electrons is crucial for characterizing any atomic or ionic species, as these numbers dictate an atom's chemical behavior and nuclear stability.
