What is the atomic number of Mercury?

80

The correct answer is option 2. 80.

The atomic number of an element is the number of protons found in the nucleus of an atom of that element. In the case of mercury (Hg), the atomic number is 80. This means that a neutral atom of mercury has 80 protons in its nucleus.

Chemical elements are organized on the periodic table based on their atomic numbers. Mercury is a metallic element and is found in Group 12 of the periodic table. It is a transition metal with the symbol Hg, and its atomic number, 80, uniquely identifies its position in the periodic table. The atomic number is a fundamental property of an element and helps determine its chemical and physical characteristics.