PLEASE HELP!! According to the shell model, which should experience the greater effective nuclear charge, an electron in

a. carbon's 1st shell or silicon's 1st shell?

b. carbon's 2nd shell or silicon's 2nd shell?

c. carbon's 2nd shell or silicon's 3rd shell?

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

Which statement is true about ionic compounds?

Which best explains why an iceberg floats?