Once you figure out the electron configuration, you fill up the corresponding orbitals with electrons, any left with one is considered unpaired. Since 1s can only hold 2 electrons, and P has 15, that's obviously filled and has no unpaired electrons. The same is for 2s which holds 2, 2p which holds 6, 3s which holds 2.
However 3p can hold 6 electrons and in order for that to be filled up you would need to have an element of 18 electrons. So you fill up as much as you can in 3p by first adding 1 electron to each energy level. 3p has 3 energy levels and there are only 3 electrons left to distribute, so each of those energy levels only gets 1, because you have to fill them all with one before you can start addin
Fractional distillation is used to separate mixtures into its component parts or fractions with the difference in boiling points between successive fractions must be more than 10°C. An example is the liquid nitrogen and oxygen are then separated by fractional distillation . There is an explanation video available below.
Polysaccharides are long chains of monosaccharides linked by glycosidic bonds. Three important polysaccharides, starch, glycogen, and cellulose, are composed of glucose. There is an explanation video available below.
The element with atomic number 17 is Chlorine with a valency of -1, that is it needs to receive an electron or possibly lose seven electrons to obey the octet rule. There is an explanation video available below.