Answer:
I think #3 might be the answer .
Because in #1 atomic mass tells mass .
#4 Atomic number doesnot only tell about the electrons atom has
B 2
is which shell are the valence electrons of the elements in period 2 found
Density=mass/volume
Mass = 0.0500g
Volume = 6.40mL
0.0500g/6.40mL = 0.0078g/mL
n = m/M = 2/18 = 1/9 ~0,1 mol
The periodic table is one of the most important tools in the history of chemistry. It describes the atomic properties of every known chemical element in a concise format, including the atomic number, atomic mass and relationships between the elements. Elements with similar chemical properties are arranged in columns in the periodic table.
The table thus is a quick reference as to what elements may behave the same chemically or which may have similar weights or atomic structures.
Hope this answer helps you
