Paper 3 · atomic structure / electron configuration
What is the order of increasing energy of given orbitals in an atom of titanium?
A3s, 3p, 3d, 4s
B3s, 3p, 4s, 3d
C3s, 4s, 3, 3d
D3s, 3d, 3p, 4s
Explanation: The marking scheme gives answer B. In titanium the order of increasing energy is 3s < 3p < 4s < 3d (noting that 4s is filled before 3d in the building-up principle, so 4s is lower in energy than 3d for transition metals during filling).
ZIMSEC Chemistry Paper 3, June 2009, Q3
