Recall that question 2 of pre-lab quiz for project 3 introduced that molarity (molar concentration) of a solution is defined as the ratio of the amount of solute in moles to the amount of solution in liters. molarity is a common unit to express solution concentration. m o l a r i t y o f a s o l u t i o n = n u m b e r o f m o l e s o f s o l u t e ( m o l ) v o l u m e o f s o l u t i o n ( l ) during the first week of this project, you need to start with preparing stock solutions for different dyes. suppose you choose to prepare the stock solution of red dye #40 by measuring 0.05 g of dye powder, and making a 100 ml dye solution with volumetric flask. what is the molarity of this stock solution (in mol/l)? (hint: convert mass of dye powder to the number of moles first using molar mass.)

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.

it is a solid

explanation: