The surface area is the largest and the contact surface of small cubes is the least, which is arranged in a row; On the contrary, the surface area is the smallest, and the contact surface of the small cube is the most, with two layers, four for each layer.

Maximum surface area:1*1* 5 * 2+1*1* 4 * 6 = 34cm2.

Minimum surface area: 1* 1*24=24 cm2.

Difference: 34-24 =10cm