an ion that has 55 protons and 54 electrons is ….
The correct answer and explanation is :
An ion that has 55 protons and 54 electrons is a Cesium ion (Cs⁺).
Explanation:
- Understanding Atomic Number and Protons
Every element is identified by its atomic number, which represents the number of protons in its nucleus. Cesium (Cs) has an atomic number of 55, meaning it has 55 protons in its nucleus. - Understanding Ions
An ion is an atom or molecule that has gained or lost electrons, resulting in a net electrical charge.
- Cations: Positively charged ions (fewer electrons than protons).
- Anions: Negatively charged ions (more electrons than protons).
- Determining the Charge of the Ion
- A neutral Cesium (Cs) atom has 55 protons and 55 electrons (protons = electrons → neutral charge).
- This ion has 55 protons but only 54 electrons.
- Since it has one fewer electron than the number of protons, it carries a +1 charge.
- Naming the Ion
- The symbol for Cesium is Cs.
- Since it has lost one electron, it forms a Cs⁺ ion.
- Why Does Cesium Form Cs⁺?
- Cesium is an alkali metal (Group 1) on the periodic table.
- Alkali metals tend to lose one electron to achieve a stable electron configuration, similar to the noble gas Xenon (Xe).
- By losing one electron, Cesium attains a stable noble gas configuration.
Conclusion
The correct answer is Cs⁺ (Cesium ion), which forms due to the loss of one electron, resulting in a +1 charge.