Not sure if this is correct but i would choose the steel tray.
Carbon has the highest Ionization energy
Explanation:
The radial distribution function gives the probability density for an electron to be found anywhere on the surface of a sphere located a distance r from the proton. Since the area of a spherical surface is 4πr2, the radial distribution function is given by 4πr2R(r)∗R(r).
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The positively charged protons in the nucleus attract the negatively charged electrons. As the number of protons in the nucleus increases, the electronegativity or attraction will increase. Therefore electronegativity increases from left to right in a row in the periodic table.