Answer:
The order will be:
CCH > CHCH₂ > CH₂CH₃> CH₃
Explanation:
According to Cahn-Ingold-Prelog system we rank the groups based on the atomic number of directly attached atom with the chiral carbon.
For example: between C and H, we rank Carbon first.
If the same atoms are attached for different groups then we prioritized based on the second element with highest atomic number.
For example:
Among CH₃ and C₂H₅, the priority will be given to C₂H₅.
If an atom is double or triple bonded to the directly attached atom then each pi bond is considered to be a new atom.
Hence CH=CH₂ means, that there are two carbons attached to CH carbon.
So the order based on above selection rules will be:
CCH > CHCH₂ > CH₂CH₃> CH₃
Answer: Elements in Group 2
Explanation: The periodic table was arranged by Dmitri Mendeleev specifically around similarites in their chemical behaviors. He found that as atomic number increases, at some point an element starts to react in a manner similar to a previous one. When that happened, he would place the larger element under the smaller one, and eventually noticed a periodicity in the table. Elements in a column (Groups) had similiar chemical properties. We know today that these similarities are due to the electron configuration, and that these configurations repeat themselves. He left gaps in the table when he could find an existing element with properties similar to others in that group. I big leap of faith, but it worked. Elements for those missing boxes were eventually discovered.
