The answer is the upper right Fluorine is the most electronegative.
Answer:

Explanation:
Hello,
In this case, the first step is to compute the volume of the block considering the length, height and width:

Then, we compute the volume in cubic centimetres:

Finally, as the density is given by:

We solve for the mass:

Best regards.
It's b. calcium
because the outer electron structure in all of that element is similar, they have the same chemical and physical properties.<span />
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days