What is the electron configuration of a ground-state Nb2+ ion? Select one: a. 1s22s22p63s23p64s23d104p65s24d1 b. 1s22s22p63s23p64s23d104p64d3 c. 1s22s22p63s23p64s23d104p65s14d2 d. 1s22s22p63s23p64s23d104p64d5 e. 1s22s22p63s23p64s23d104p65s24d3

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.