Which of the following statements regarding the mole is incorrect?
1) A mole is a counting unit equal to 6.02 x 10²³ particles.
2) The mole is a unit that cannot be changed into any other unit.
3) The number of particles in a mole is known as Avogadro's number.
4) A mole of particles of an element is numerically equal to the atomic mass of the element.