Answer:
For X, recall that the isotope notation uses the following symbols:
A
Z
X
±
n
Z
is the atomic number, which tells you the number of protons in the element and also its identity.
A
is the mass number, which tells you the number of protons plus the number of neutrons.
X
is the chemical symbol of the element, and it must correspond to the atomic number.
±
is the signed charge.
Explanation:
