Hey there!:
Molar mass Lead ( Pb ) = 207.2 g/mol
Therefore:
1 mole Pb --------------------- 6.02*10²³ atoms
? moles Pb -------------------- 2.31*10²¹ atoms
moles Pb = ( 2.31*10²¹ ) * 1 / ( 6.02*10²³ ) =
moles Pb = ( 2.31*10²¹ ) / ( 6.02*10²³ ) =
=> 0.00383 moles of Pb
Hope this helps !
atoms consist of protons and neutrons in the nucleus , surrounded by electrons that reside in orbitals . Orbitals are classified according to the four quantum number s that represent anyone particular orbitals energy , shape , orientation and the spin of the occupying electron.
hope this helps xx
The greatest aqueous freezing point is (D) 0.10 KCI
63/29 Cu (copper-63)
65/29 Cu (copper-65)
24/12 Mg (magnesium 24)
25/12 Mg (magnesium 25)
26/12 Mg (magnesium 26)
6/3 Li (lithium 6)
7/3 Li (lithium 7)
The top number is the mass number and you find that by adding the number of neutrons and atomic number
The bottom number is the atomic number and it’s the number or protons
