Need !

which of the following is true about the concept of half-life?

a. half-life measures the rate of decay of a radioisotope.

b. the shorter the half-life, the more dangerous the radioisotope.

c. half-life predicts which atoms in a radioactive sample will decay.

Label a-f based on the table using c for concentrated and d for dilute

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

Achemistry student weighs out 0.306 g of citric acid (h3c6h5o7), a triprotic acid, into a 250 ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.1000 m naoh solution. calculate the volume of naoh solution the student will need to add to reach the final equivalence point. be sure your answer has the correct number of significant digits.