You may have to recrystallize any or all of the components of your extraction mixture, benzoic acid, ethyl-4-aminobenzoate and fluorenone, depending on their purity after isolation. You should have the recystallization solvents in your protocol. They are respectively:

the Recrystallization solvents are;

-Sodium Hydroxide Base (NaOH)

- Hydrochloric Acid (HCl)

- Sand bath when acidic and basic components are removed.

Explanation:

Recrystallization is simply a technique used to purify an impure compound in a solvent.

Now, we want to purify the mixture of benzoic acid, Ethyl-4-aminobenzoate and fluorenone.

For the benzoic acid, it can be separated out of the mixture by addition of sodium hydroxide base (NaOH).

The Ethyl - 4 - aminobenzoate will be separated from the mixture by the addition of Hydrochloric Acid (HCl).

The fluorenone would be separated out by heating the mixture in a sand bath after the basic and acidic components have already been extracted out.

Thus, the Recrystallization solvents are;

-Sodium Hydroxide Base (NaOH)

- Hydrochloric Acid (HCl)

- Sand bath when acidic and basic components are removed.

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.