chem ct 2

Question 1

aufbau principle

Answer 1

electrons occupy the 4s orbital before 3d as 4s orbitals are at a lower energy level than 3d orbitals

Question 2

Hund’s rule

Answer 2

orbitals of a sub shell must be occupied singly by electrons of parallel spins before pairing can occur to minimise inter-electronic repulsion

Question 3

Pauli exclusion principle

Answer 3

each orbital holds a maximum of 2 electrons and must be of opposite spins