Question

select the correct answer
which of these periods contain elements with electrons in s, p, d, and f orbitals?
a. periods 1-3
b. periods 1-4
c. periods 3-5
d. periods 6-7

Explanation:

Electron orbitals are filled in order of increasing energy. s orbitals appear in period 1, p orbitals in period 2, d orbitals in period 4, and f orbitals are filled by elements in periods 6 and 7 (the lanthanides and actinides, which use 4f and 5f orbitals respectively). Only periods 6 and 7 include elements with electrons occupying all four orbital types (s, p, d, f).

Answer:

D. periods 6-7