[susan53]

No, that'a not the reason. Every consonant is described with three terms - voiced vs unvoiced (whether the vocal cords are vibrated when the sound is made); place of articulation (where in the vocal tract the sound is made) and manner of articulation (how it is made acoustically). So eg /p/ is an unvoiced bilabial plosive (or stop) and /v/ is a voiced labiodental fricative. The terms plosive/stop are alternative terms referring to the manner of articulation of the sound - ie how it is actually produced. Plosive/stop sounds are made by momentarily blocking (or stopping - hence the term) the airflow from the lungs by "closing" its passage with two articulators (parts of the vocal tract). So eg for /p/ and /b/ which are bilabial sounds (place of articulation), the airflow is stopped by closing the two lips. For /t/ and /d/, which are alveolar sounds (place), the airflow is stopped by bringing the front of the tongue up to the alveolar ridge just behind the teeth; for /k/ and (g/ the airflow is stopped by bringing the back of the tongue up to the velum or soft palate (again, the place of articulation. The air builds up behind the two articulators and then is suddenly released, so that it "explodes" outwards - hence the term plosive.

So "stop" and "plosive" refer to the two successive phases of the production of the sound - the manner of articulation. Nothing else. the VPM description of the sounds you specify would be

/p/ unvoiced bilabial plosive (or stop)
/b/ voiced bilabial plosive (or stop)
/t/ unvoiced alveolar plosive (or stop)
/d/ voiced alveolar plosive (or stop)
/k/ unvoiced alveolar plosive (or stop)
/g/ voiced alveolar plosive (or stop)