Aradioactive isotope of radium (ra-226) has a half life of 1620 years. how much of this isotope remains after three (3) half-lives
1/8
none
1/4
1/2

One mole of zinc has a mass of 65.4 grams. approximately how many atoms of zinc are present in one mole of zinc? 32 × 1023 atoms 6 × 1023 atoms 66 atoms 65 atoms

Which type of bonding involves the complete transfer of a valence electron from a less electrogrative atom to a more electronegative one

4. absorption has the highest risk of overdose due to increased potency. a. rectal b. oral c. transdermal d. intranasal