The notation of an atom is given by ${}_{\mathrm{x}}{}^{\mathrm{y}}\mathrm{A}$. If the atom has 9 protons and 10 neutrons, then the respective values of x and y are ______.

In the notation, ${}_{\mathrm{x}}{}^{\mathrm{y}}\mathrm{A}$, x and y respectively represent the atomic number and mass number of A.

An atomic number of an element is the number of protons present in the atom of that element. A mass number of an element is the sum of the number of protons and neutrons present in the atom of that element.

Number of protons = 9 (given)

Number of neutrons = 10 (given)

Therefore, the atomic number of the given element = 9

Mass number of the given element = 9 + 10 = 19

Thus, x = 9 and y = 19.