Question

what element is designated by the orbital diagram below? (note that core electrons are not shown.) 3d 4s

Explanation:

Step1: Count valence electrons

Count electrons in 3d and 4s: $3d^8 + 4s^2 = 10$ valence electrons

Step2: Find total electron count

Assume neutral atom: core electrons + valence electrons = [Kr core] + 10 = 36 + 10 = 46

Step3: Match to element

Atomic number 46 corresponds to Palladium? No, correct: 4s²3d⁸ is Nickel? No, wait: 36 (Kr) + 10 = 46 is Pd, but Pd has 4d¹⁰. Wait, no: 4s²3d⁸ is atomic number 28 (Ar core 18 + 10 = 28). Correct: Ar (18) + 2+8=28.

Answer:

Nickel (Ni)