ALPHA PARTICLE Helium nuclei. Not very penetrating. Stopped by epidermis. BECQUEREL Symbol: Bq 1 disintegration/second. 1 Curie = 3.7 x 10^10 Bq. Unit of activity. Things with small half-lives have the biggest activity. BERYLLIUM Symbol: Be Element 4 with atomic weights b/w 6 and 11. A neutron reflector and neutronContinue Reading