How many atoms of phosphorus are in 8.10 mol of copper(ii) phosphate?

Similar to what 'Rosael' noted (thanks Rosael!) instead of just multiplying the 2 mols that Phosphorus has, in it's Cu3(PO4)2 compound... we need to recognize that the total amount of moles in 8.10 moles of the compound is actually (2 mols P x 8.10 mols of Cu3(PO4)3) from here we know that Cu3(PO4)2 contains 16.2 mols of P but because we are asked to figure out how many ATOMS 16.2 MOLS of P actually are... this is where we utilize Avagadro's wonderful # (i saw wonderful because it magically helps us switch back and forth from these sorts of things.)

We do this by saying:

16.2 mols of P x ( 6.022x10^23 atoms of P ) / 1 mol of P

writing this out will help you to see how the mols then cancel, and we end up only with atoms of P *Rember that Avagadro's # is there to help! It may not always go on top... sometimes you will need to divide by it to find how many mols is in something...* Hope this helped!

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.