Where is the atomic mass number indicated on a chemical symbol according to the material?

Where is the atomic mass number indicated on a chemical symbol according to the material?

• A. Upper left corner
• B. Lower left corner
• C. Upper right corner
• D. Lower right corner

Answer: (B)

The atomic mass number A is the total number of protons and neutrons in a nucleus, and it is shown as a superscript to the left of the element symbol (in the upper left corner). The atomic number Z, counting protons, is placed as a subscript to the left (lower left), and any electric charge appears as a superscript to the right (upper right). So, the mass number is positioned in the upper left corner to indicate A.

The atomic mass number A is the total number of protons and neutrons in a nucleus, and it is shown as a superscript to the left of the element symbol (in the upper left corner). The atomic number Z, counting protons, is placed as a subscript to the left (lower left), and any electric charge appears as a superscript to the right (upper right). So, the mass number is positioned in the upper left corner to indicate A.