When sodium atom form the ion Na+,
- it gains one proton
-
it achieves a noble gas configuration
- its atomic number increases
- it gains one electron
The correct answer is: B
Explanation
When the sodium atom forms an ion, Na+ it loses one electron, i.e. it achieves a noble gas electronic configuration. It will lose one of its 11 electrons to have 10 electrons like neon.
\(Na - e^- → Na^+\)
Na → \(Na^+ + e^-\)