In Clifford algebra, it would be found that spinors or spin group, where spinors are essential in describing spin as an intrinsic quantum property in quantum electrodynamics with the general nature of an intrinsic angular momentum of subatomic particles, and pinors or pin group, where pinors may be expected essential in describing pin as a further intrinsic quantum property in quantum electrodynamics with the general nature of an intrinsic linear momentum of subatomic particles. The physical consequences of spin and pin may be obtained in the phenomenon of uniform circular motion of a rotating point object about its axis of rotation such that spin is along the axis of rotation to the plane of rotation of the object and pin, like a tiny string, may be about the same axis of rotation on the plane of rotation of the object. As such, if spin is considered as an intrinsic quantum property of subatomic particles in quantum electrodynamics, then pin would also be considered as a further intrinsic quantum property of subatomic particles in quantum electrodynamics, where these two intrinsic quantum properties of subatomic particles, spin and pin, would be found perpendicular to each other. Therefore, spin and pin, by acting at right angle to each other in any reference frame, being quantized, would represent the observable quantum states such as subatomic particles in quantum mechanics and particle physics. It would also be found that a spin is associated together with an intrinsic magnetic moment along the same axis of rotation to the plane of rotation at ntiparallel to spin, and a pin may be associated together with an intrinsic electric moment about the same axis of rotation on the plane of rotation at antiparallel to pin in quantum electrodynamics. Thus, the presence of the four intrinsic properties — spin, pin, magnetic moment and electric moment — of subatomic particles in quantum electrodynamics may open a new perspective of quantum mechanics and particle physics, which may support to find out the isolated quantized electric mono-poles as free positive and negative electric charges, as well as, the isolated quantized magnetic mono-poles as free positive and negative magnetic charges carried by specific particles.