The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
Answer Details
Chlorine has 17 electrons because it has 17 protons, which is its atomic number. A chloride ion (Cl-) has gained one electron to form a negative ion. Therefore, it now has one more electron than the number of protons (which is still 17). This means that a chloride ion has 18 electrons. So, the answer is (c) 18.