D-1 electron in their outer energy level.
Physical changes are when things get changed without altering chemical consistencies, which is melting solid butter into liquid one, or boiling water. Chemical changes are things such as caramelizing sugar when making sweets, or when carbon dioxide is created and released when baking bread.
Answer:
The structures are attached in file.
Hydrogen bonding and intermolecular forces is the reason for ranks allotted.
Explanation:
In determining Lewis structure, we calculate the overall number of valence electrons available for bonding. Making carbon (the least electronegative atom) the central atom in the structure, we allocate valence electrons until each atom has achieved stability.
In order of decreasing affinity to water molecules:
This is due to the fact that the 
will accept protons more readily than the bicarbonate ion, 
. Carbonic acid, 
will not accept any more protons, hence it is the least attractive to water molecule, even though soluble.
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
⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️⚱️2 one.
