Chlorine Atom vs Chloride Ion
The elements in the periodic table are not stable except the noble gases. Therefore, elements try to react with other elements, to gain the noble gas electron configuration to achieve stability. Likewise, chlorine also has to get an electron to achieve the electron configuration of the noble gas, Argon. All metals react with chlorine, forming chlorides. Except some similarities, Chlorine and chloride has different physical and chemical properties due to the change of one electron.
Chlorine is an element in the periodic table which is denoted by Cl. It is a halogen (17th group) in the 3rd period of the periodic table. The atomic number of chlorine is 17; thus, it has seventeen protons and seventeen electrons. Its electron configuration is written as 1s2 2s2 2p6 3s2 3p5. Since the p sub level should have 6 electrons to obtain the Argon noble gas electron configuration, chlorine has the ability to attract an electron. Chlorine has a very high electro negativity, which is about 3, according to the Pauling scale. The atomic weight of chlorine is 35.453 amu. Under room temperature, chlorine exists as a diatomic molecule (Cl2). Cl2 is a yellow – greenish color gas. Chlorine has a melting point of -101.5 °C and a boiling point of -34.04 °C. Among all the chlorine isotopes, Cl-35 and Cl-37 are the most stable isotopes. In the atmosphere, 35Cl present in 75.77% and 37Cl present in 24.23%. When chlorine gas is dissolved in water, it forms hydrochloric acid and hypochlorous acid, which are highly acidic. Chlorine has all the oxidation numbers varying from -1 to +7.
Chloride is the resulted anion when chlorine abstracts an electron from another electropositive element. Chloride is represented by the symbol Cl–. Chloride is a monovalent ion with -1 charge. Therefore, it has 18 electrons and seventeen protons. The electron configuration of chloride is 1s2 2s2 2p6 3s2 3p6. Chloride exists in ionic compounds such as sodium chloride, calcium chloride and HCl, which are ionic. Chloride also exists naturally in water sources, and this is the most common anion in the nature. There is a considerable amount of chloride ions in sea water. Chloride ions can participate in conducting electricity through solvents.
What is the difference between Chlorine Atom and Chloride Ion?
• Chloride ion is the reduced form of chlorine atom. Chloride has 18 electrons compared to seventeen electrons of chlorine, and both have seventeen protons. Therefore, chloride has a negative (-1) charge whereas chlorine is neutral.
• Since there is an additional electron in the chloride ion than the atom, the ionic radius differs from the atomic radius of chlorine. With additional electron in the outer shell, chloride ion tends to expand due to the electron repulsion between each other. This causes an increase in ionic radius for chloride than the chlorine atomic radius.
• Chlorine is more chemically reactive than chloride because it is more unstable.
• Chloride has achieved the Argon electron configuration, therefore, stable than the chlorine atom.
• Chloride ion is attracted to positively charged electrodes or other positively charged chemical species, but chlorine does not.