Two atoms of the same element have the atomic number 17 but different mass numbers of 35 and 37. These two atoms are:

The table below shows information about three elements X, Y, and Z. Some values are missing and are represented by l, m, and n. ElementAtomic numberMass numberNumber of neutronsX1123lY1735mZn4020 The values of l, m, and n are respectively:

The maximum number of electrons that can be accommodated in the third shell (M shell) of an atom is: