Which of the following statements are true?

A. The element with a ground state electron configuration of 1s22s22p63s2 is an alkaline earth metal.

B. The ground state electron configuration for the undiscovered element 115 is (Rn) 7s25f146d107p3.

C. The element with a ground state electron configuration of (Kr) 5s24d105p5 has 15 valence electrons.

D. The ground state electron configuration for Cu is (Ar) 4s13d10.

E. The electron configuration of 1s22s22p63s23p64s13d8 is an excited state electron configuration for Ni.

F. If an element (abbreviated X) has a ground state electron configuration of (Ne) 3s23p4, then the formula of the compound that X forms with sodium is Na2X.

Answer:If an element (abbreviated X) has a ground state electron configuration of (Ne) 3s23p4, then the formula of the compound that X forms with sodium is Na2X. True

The element with a ground state electron configuration of 1s22s22p63s2 is an alkaline earth metal. True

The element with a ground state electron configuration of (Kr) 5s24d105p5 has 15 valence electrons. True

The ground state electron configuration for Cu is (Ar) 4s13d10. True

Explanation:

The ground state electron configuration for the undiscovered element 115 is (Rn) 7s25f146d107p3. Is not the correct electron configuration for the element moscovium. It is no longer undiscovered but is now well known. The correct electron configuration is Moscovium: [Rn]5f14 6d10 7s2 7p3 OR

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 5f14 6d10 7s2 7p3.

The electron configuration of 1s22s22p63s23p64s13d8 is an excited state electron configuration for Ni ... This statement has to be false because the excited electron must be promoted to a higher energy level. Which was not reflected in the configuration written above.