Given a diagram of an atom showing 6 protons, 6 neutrons, and 6 electrons, which of the following correctly completes the table for atomic number, mass number, and element symbol?

• A. Atomic number: 12; Mass number: 6; Element symbol: O
• B. Atomic number: 6; Mass number: 12; Element symbol: C
• C. Atomic number: 6; Mass number: 6; Element symbol: N
• D. Atomic number: 12; Mass number: 12; Element symbol: Mg

Answer: (B)

Verified step by step guidance

1. Identify the atomic number, which is the number of protons in the atom. In this case, the atom has 6 protons, so the atomic number is 6.
2. Determine the mass number by adding the number of protons and neutrons. Here, there are 6 protons and 6 neutrons, so the mass number is \$6 + 6 = 12$.
3. Use the atomic number to find the element symbol from the periodic table. An atomic number of 6 corresponds to the element carbon, symbolized as 'C'.
4. Verify that the mass number and atomic number match the element symbol. For carbon, the common isotope has a mass number of 12, which aligns with the given numbers.
5. Conclude that the correct completion of the table is: Atomic number = 6, Mass number = 12, Element symbol = C.