Polonium-208 is an alpha emitter with a half-life of 2.90 years. how many milligrams of polonium from an original sample of 2.00 mg will remain after 8.00 years? a) 0.147 mg b) 0.296 mg c) 0.725 mg d) 6.77 mg e) 1.90 mg.

The answer to your question is letter B.

Explanation:

Data

Polonium-208 half-life = 2.9 years

Original sample = 2 mg

Total time = 8 years

Process

                     Mass                  Time

                     2 mg                 0 years

                     1 mg                   2.9 years

                      0.5 mg              5.8 years

                      0.25 mg            8.7 years

The mass of sample must be between 0.5 and 0.25 mg, from the options given the only possible answer is letter B 0.296 mg

"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."

the temperature of the gas, in k, not celsius.