Use the standard enthalpies of formation for the reactants and products to solve for the AH, xn for the following reaction. (The AH, of HCN is 108.9 kJ/mol, AgCl is -127.068 kJ/mol, HCl is -167.159 kJ/mol and AgCN is 146.0 kJ/mol.)
HCl (aq) + AGCN (s) → HCN (aq) + AgCl (s)
AHxn =
The reaction is

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.

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