The mole is a counting number that allows scientists to describe how individual molecules and atoms react. If one mole of atoms or molecules is equal to 6.022 × 1023 atoms or molecules, how many molecules are in a 23.45 g sample of copper (II) hydroxide, Cu(OH)2? Express your answer to the correct number of significant figures. (MM of Cu(OH)2 is 97.562 g/mol). Be sure to show all steps completed to arrive at the answer

Mass of Cu(OH)2 = 23.45 g

Molar mass of Cu(OH)2 = 97.562 g/mol

Since we know,

Moles = Mass/Molar mass

\Rightarrow Moles = (23.45 g)/(97.562 g/mol) = 0.2404 moles

Since 1 mole of substance contains = 6.022 × 1023 molecules

So 0.2404 moles will contain = 0.2404*(6.022 × 1023 molecules) = 1.448 × 1023 molecules

its first and third is your answer i did the qustion the fourth isnt right

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.