To determine the symbol for an atom, we need to identify the element based on its atomic number and then indicate the mass number.
Given that the atom has 12 neutrons and 11 electrons, we can calculate the atomic number by adding the number of protons (which is equal to the number of electrons) to the number of neutrons. Since the atom has 12 neutrons and 11 electrons, the atomic number would be:
Atomic number = Number of protons = Number of electrons = 11
To determine the element, we can refer to the periodic table, where we find that the element with an atomic number of 11 is sodium (Na).
Now, to indicate the mass number, we add the number of protons (which is the atomic number) to the number of neutrons:
Mass number = Atomic number + Number of neutrons = 11 + 12 = 23
Therefore, the symbol including the mass number and atomic number for an atom of sodium with 12 neutrons and 11 electrons is:
^23Na