The stepwise stability constants (log Kn) for the formation of the octahedral cations, [Ni(en)3]2+ and [Cu(en)3]2+, are given below. lon Ni+ Cu2+ log K1 7.7 10.7 log K 6.3 9.3 log K3 4.3 -1.0 For [Ni(en)3]2+, express the overall stability constant (3) in terms of K1, K2 and K3. Determine log 3 for [Ni(en)3]2+. Comment on the trend in the log Kn values for [Ni(en)3]2+. Compare the log Kn data for both cations and account for the very low value of log K3 for Cu+