It's B, because a negative charged Ion is an anion. And since it's 1- ,one valence electron is been added to H. So it has 2 valence electrons.
Answer:
Higher levels of organization are built from lower levels. Therefore, molecules combine to form cells, cells combine to form tissues, tissues combine to form organs, organs combine to form organ systems, and organ systems combine to form organisms.
In preparing diluted solutions from concentrated solutions we can use the following formula
c1v1 = c2v2
c1 and v1 are the concentration and volume of the concentrated solution respectively
c2 and v2 are the concentrations and volume of the diluted solution respectively
Substituting these values ,
20 mL x 1.0 M = C x 60 mL
C = 0.33 M
The concentration of the resulting diluted solutions is 0.33 M
I am answering A question
Mg+2HCl-->H2+MgCl2 you would it have to make it so each is equal on each side you would add a 2 on left in front of HCl because on the other side there is already 2 H and 2Cl so just put a 2 in front of HCl