Look at the simplified Periodic Table in the attachment. Each letter represents an element but the letter is not the real chemical symbol.
Use your knowledge to sort the letters to say whether they are metal
or non-metal elements.
W
Y
V
Z
x

According to this picture w and y are metals and v z and x are non metals

Explanation:

The given question is incomplete, the complete question is:

Suppose the amount of a certain radioactive substance in a sample decays from 1.30 mg to 100. ug over a period of 29.5 days. Calculate the half life of the substance Round your answer to 2 significant digits.

The correct answer is 7.974 days.

Explanation:

Based on the given question, the concentration of a radioactive substance present in a sample get decays to 100 micro grams from 1.30 milligrams in 29.5 days. There is a need to find the half-life of the substance.  

Radioactive decay is an illustration of first order reaction.  

K = (2.303 / t) log [a/(a-x)]

Here a is 1.30 mg and (a-x) is 100 micrograms = 100 * 10^-3 mg or 0.1 mg, and t is 29.5 days. Now putting the values we get,  

K = (2.303 /29.5)log (1.30/0.1)

= 2.303/29.5 log13

= 2.303/29.5 * 1.1139

K = 0.0869

The half-life or t1/2 is calculated by using the formula, 0.693 / K

= 0.693 / 0.0869

= 7.974 days.