Final answer:
The symbolic notation for an atom with 5 protons and 7 neutrons is ^12_5B, representing the element boron with a mass number of 12.
Step-by-step explanation:
To write the symbolic notation for an atom with 5 protons and 7 neutrons, we first need to identify the chemical element by its atomic number, which is equal to the number of protons. The element with 5 protons is boron, which has the chemical symbol B. The mass number of an atom is the sum of its protons and neutrons, which in this case is 5 + 7 = 12. The symbolic notation includes the element's symbol (B), the mass number at the upper left (12), and the atomic number at the lower left (5).
Therefore, the complete symbolic notation for an atom of boron with 7 neutrons is ^12_5B. If the atom is neutral, it would have the same number of electrons as protons, which is 5 in this case. If the atom is charged, we would need to specify this in the symbol, but as the question does not mention a charge, we assume the boron atom is neutral.