What volume of 10.0 M HCl is needed to contain 4.00 moles of HCl?

Volume of 10M HCl containing 4 moles HCl = 400 ml

Explanation:

Molarity x Volume (L) = moles

10M·V = 4 moles HCl

V = 4moles/10Molar = 4moles/10moles/Liter = 0.40L = 400ml

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.