How many valence electrons are in a neutral atom of xenon (Xe) ?
The correct answer and explanation is:
A neutral atom of xenon (Xe) has 8 valence electrons.
🔬 Explanation (300 words):
Xenon (Xe) is a chemical element with the atomic number 54, meaning it has 54 protons and, in its neutral state, 54 electrons. These electrons are arranged in energy levels or electron shells surrounding the nucleus.
To determine the number of valence electrons, we need to look at xenon’s position in the periodic table. Xenon belongs to Group 18, also known as the noble gases. The elements in Group 18 all have a full outer electron shell, which makes them chemically stable and largely unreactive.
Here’s how the electrons of xenon are distributed among its shells:
- 1st shell: 2 electrons
- 2nd shell: 8 electrons
- 3rd shell: 18 electrons
- 4th shell: 18 electrons
- 5th shell: 8 electrons (valence shell)
The outermost shell (5th shell) contains 8 electrons, which are the valence electrons. Valence electrons are the electrons in the outermost energy level of an atom and are primarily responsible for chemical bonding and reactivity.
Because xenon has a full valence shell, it is generally non-reactive under standard conditions. However, unlike lighter noble gases like helium and neon, xenon can form compounds under special conditions, especially with highly electronegative elements like fluorine and oxygen (e.g., XeF₂, XeO₃). This is due to xenon’s relatively large atomic size and the presence of empty d orbitals, which can be used in bonding.
In summary, xenon has 8 valence electrons, corresponding to its complete and stable outer shell. This electron configuration explains its chemical inertness and its classification as a noble gas.