Question

why does the na+ ion have a +1 charge?
it has gained an extra proton.
it has gained an extra electron.
it has lost a proton.
it has lost an electron.

Explanation:

Ions are formed when atoms gain or lose electrons. Protons are in the nucleus and are not easily lost or gained in normal chemical reactions. Sodium (Na) has 11 protons and 11 electrons in its neutral state. When it loses one electron (which has a negative charge), the number of protons (positive charge) is one more than the number of electrons. So, the ion \(Na^+\) has a +1 charge. Gaining an extra proton would change the element (since the number of protons defines the element). Gaining an extra electron would make it negatively charged (\(Na^-\)). Losing a proton would also change the element.

Answer:

It has lost an electron.