How do atomic mass and atomic number change across and dow the periodic table of elements?

How many moles of cu are needed to react with 5.8 moles of agno3? cu + 2 agno3 → cu(no3)2 + 2 ag

Two nails have identical sizes and shapes. in one nail, 20 percent of the domains are lined up. in the other nail, 80 percent of the domains are lined up. which has stronger magnetic force? first answer gets brainliest!

Animals that reproduce sexually either do it through external or internal fertilization. read the following statement and decide if it is true or false. birds reproduce through external reproduction which is because the female will then be able to protect the egg.