D an average train goes 300 km/h or 190-220 mph
So the equation is balanced, meaning they have the smallest amounts of each element in the reactants to create the products.
So, 2 moles of H2S (the coefficient) contributes to 2 moles Ag2S, which is why the ratio is 2:2.
I hope that made sense.
So I believe you are supposed to take notes based on the guiding questions (the questions on the side).
Zeff = Z - S
Here, Z is the number of protons in the nucleus, that is, atomic number, and S is the number of nonvalence electrons.
For boron, the electronic configuration is 1s₂ 2s₂ 2p₄
Z = 5, S = 2
Zeff = 5-2 = +3
For O, electronic configuration is 1s₂ 2s₂ 2p₄
Z = 8, S = 2
Zeff = 8-2 = +6
Hence, the correct answer is second option, that is, +3 and +6, the Zeff of boron is smaller in comparison to O, thus, boron exhibits a bigger size than O.
