Arectangular piece of platinum has dimensions of 3.50 cm*2.16 cm*1.08 cm and weighs 175.5 g. what is the density of platinum?

21.5 g/cm³

Explanation:

We define density as mass / volume.

We have the mass of the Pt piece → 175.5 g

Therefore, we must find out the volume with the data of dimensions:

3.50 cm . 2.16 cm . 1.08 cm = 8.16 cm³

Density is 175.5 g / 8.16 cm³ = 21.5 g/cm³

As you go across each period from left to right the outer shell gradually becomes filled with electrons. the outer shell contains just one electron on the left hand side of the table, but is filled by the time you get to the right hand side.moving  down each group, you can see that  the number of electrons in the outermost shell is the same as the group number number.each element in a group therefore has the same number of electrons in its outer shell.i hope it you!