d-orbitals are a type of atomic orbital found in the electron configuration of transition metals and some heavier elements. They can hold a maximum of ten electrons and are characterized by their unique shapes, which include cloverleaf patterns and a donut-like ring. There are five different d-orbitals in each energy level starting from the third level (n=3). These orbitals play a crucial role in the chemical properties of elements, particularly in bonding and electron interactions. The presence of d-orbitals allows for complex electron arrangements, contributing to the formation of various compounds and influencing the color and magnetism of transition metals.