What would you expect to see if a piece of copper metal is placed in a solution that contains nickel(II) ions? A. copper atoms become copper(II) ions
b. nickel ions become solid nickel
c. no reaction happens
d. a precipitate forms that contains copper and nickel ions

c. no reaction happens

Explanation:

Let me take your mind back to the idea of electrode potentials of metals. Remember that the more negative the electrode potential of a metal, the more reducing the metal is. Metals with more negative electrode potentials displace metals with less negative electrode potentials from their aqueous solutions.

The electrode potential of nickel is -0.25 V while that of copper is +0.34 V. Hence, copper is lower than nickel in the activity series and can not displace it from aqueous solution.

This implies that, if a piece of copper metal is placed in a solution that contains nickel(II) ions, no reaction happens .

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.