A sodium ion, Na+, has a positive charge because it
A.
gained an electron.
B.
lost a proton.
C.
gained a neutron.
D.
lost an electron.
D. lost an electron.
A sodium ion, Na+, has a positive charge because it lost an electron.
The atomic number of sodium is 11, which means a neutral sodium atom has 11 protons and 11 electrons. However, when sodium loses an electron, it becomes a positive ion with a charge of +1.
To determine why a sodium ion, Na+, has a positive charge, let's examine the options and the process for determining the charge of an ion.
An ion is formed when an atom gains or loses electrons. Electrons are negatively charged particles, so when an atom gains electrons, it becomes negatively charged (+e). Conversely, when an atom loses electrons, it becomes positively charged (-e).
Now, we can evaluate the given options:
A. Gained an electron: If sodium (Na) gained an electron, it would have one more electron than protons, resulting in a negative charge. Therefore, this option is not correct.
B. Lost a proton: Protons are positively charged particles found in the nucleus of an atom. In general, ions do not lose protons because altering the number of protons changes the identity of an element. Sodium (Na) always has 11 protons, so this option is not correct.
C. Gained a neutron: Neutrons are electrically neutral particles found in the nucleus of an atom. Since neutrons have no charge, adding or removing them doesn't affect the overall charge of an ion. Therefore, this option is not correct.
D. Lost an electron: Sodium (Na) has 11 electrons in its neutral state. By losing one electron, it would have 10 electrons, but its number of protons would remain the same. This results in a net positive charge, making it a sodium ion, Na+.
Based on the explanation provided, we can conclude that option D is correct: a sodium ion, Na+, has a positive charge because it lost an electron.