Please Help 1. What is the parent isotope when Rn-218 is formed as a result of an alpha decay? A. At-212
B. Ra-88
C. Ra-222
D. Ac-228

2. What is the parent isotope when Holmium-166 is formed during an alpha decay?

A. Tm-170
B. Er-170
C. Tb-160
D. Dy-164

Express the following number in scientific notation. 0.026890 =

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.