Based on the placement on the Periodic Table, what set of elements have the same number of electron shells?
A Hydrogen (H), Helium (He), and Lithium (Li)
B Carbon (C), Nitrogen (N), and Oxygen (O)
C Titanium (Ti), Zirconium (Zr), and Hafnium (Hf)
D Boron (B), Silicon (Si), and Arsenic (As)

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g