Electron Configuration and Periodic Table True and False Questions?? 1. Period 5 elements have six 4p electrons 2. The valence electrons of group 4A elements are in the 5 s subshell 3. Group 8A elements have full outer principle s and p subshells 4. The valence electrons of group 3A elements are in an s and p subshell 5. The highest principle quantum number of period 4 elements is 5 6. Period 3 elements have an inner electron configuration of (Ar) 7. Period 5 elements have an inner electron configuration of (Kr) 8. The highest principle quantum number of period 4 elements is 4