All radioactive sources have a half-life. Which statement about the half-life of a source is correct?

A. It is half the time it takes for an atom to decay

B. It is half the time for the radioactive source to become safe

C. It is the time it takes the actity of the source to decrease by half

D. It is half the time it takes the activity of the source to decrease to zero

The answer is C

Explanation:

Duh its the name HALF LIFE!!

just a way to remember

answer; protein;

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."