The interaction of electrons and the nucleus changes when the atomic number changes and count for electrons changes. An alternate method for predicting electron subshells filling order is shown with the diagram below. This triangle can be built and used to predict the electron configuration for most any atom. Each successive row has an n value larger by one unit. The top of the diagram matches the top of the periodic table.
Every column has the same subshell type.
Population limits for subshells The maximum population for each subshell type is listed at the bottom of the diagram. Each of the s subshells can only hold 2 electrons. Each of the p subshells can only hold 6 electrons. Each of the d sublevels can hold 10 electrons. NOTE the pattern of an increase of 4 additional electrons for each succeeding subshell.