How many electrons, protons and neutrons are found in the +2 cation of the Barium -140 isotope.
The Correct Answer and Explanation is:
Correct Answer:
The +2 cation of Barium-140 has:
- Electrons: 54
- Protons: 56
- Neutrons: 84
Explanation
To determine the number of electrons, protons, and neutrons in the +2 cation of Barium-140, we begin by analyzing the atomic structure of the neutral atom of barium.
Barium is a chemical element with the atomic number 56, which means a neutral atom of barium has 56 protons and 56 electrons. The atomic number defines the number of protons in the nucleus of an atom and also determines the element’s identity.
The term “Barium-140” refers to the isotope of barium with a mass number of 140. The mass number is the total count of protons and neutrons in the nucleus. Since barium always has 56 protons, the number of neutrons in this isotope is calculated by subtracting the number of protons from the mass number:
140 (mass number) – 56 (protons) = 84 neutrons
Now, consider the +2 cation of Barium-140. A cation is a positively charged ion, formed when an atom loses one or more electrons. The +2 charge indicates that two electrons have been lost. Therefore, the number of electrons in the +2 cation is:
56 (original electrons in neutral atom) – 2 = 54 electrons
To summarize:
- The number of protons remains constant at 56 because removing electrons does not affect the nucleus.
- The number of neutrons is 84, based on the isotope’s mass number.
- The number of electrons is reduced to 54 due to the +2 charge.
These properties help explain how ions behave in chemical reactions and influence the atomic structure and reactivity of elements like barium.
