1. SI,
2. Number 10.
I'm pretty sure it's that, I just did something related to that.
Going down A-D
Going across is 1-4
A 4
B 3
C 1
D 2
Hope this helps! Brainliest?
Have a great day :)
Answer:
The small number behind each element symbol designates the number of atoms of each element in a chemical formula. If there is no number, it is assumed there is only one of those elements. A large number in front of a compound designates how many units there are of that compound.
