The ion Na+ (sodium ion) has 11 protons and 10 electrons.
To understand this, we first need to look at what sodium is in its neutral state. Sodium (Na) has an atomic number of 11, which means it has 11 protons in its nucleus. In a neutral atom, the number of protons equals the number of electrons, so a neutral sodium atom also has 11 electrons.
However, when sodium loses one electron to form the Na+ ion, it becomes positively charged. This loss of one electron reduces the total number of electrons in the ion to 10, while the number of protons remains unchanged at 11. Thus, the sodium ion Na+ contains 11 protons and 10 electrons.