4) After three half-lives of an isotope, 1 billion (one-eighth) of the original isotope's atoms still remain in a certain amount of this element. How many atoms of the daughter product would you expect to be present?

7 * 10^9 atoms

Explanation:

We must first find the number of atoms originally present. We can do this by considering the information given in the question that one-eight of the original isotope is left and that is about one billion atoms of the original material left. Let the number of atoms originally present be x.

So;

1/8x = 1 * 10^9

x = 8/1 * 1 * 10^9

x = 8 * 10^9 atoms of radioactive material.

Number of atoms of daughter nucleus present=

x- 1/8x = 7/8x

but x = 8 * 10^9 atoms of radioactive material

Therefore;

7/8 * 8 * 10^9 atoms = 7 * 10^9 atoms

true

explanation:

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.