The element oxygen has valence electrons. (Input only a whole number, such as 7.) Numerical Answers Expected! Answer for Blank 1:

7 valence electrons.

Explanation:

Oxygen lies in period 2 and group 16 of the periodic table. It is eighth element on the periodic table. Its symbol is O.

Its electronic configuration is given by:

16 = 2,8,6

It has 6 valance electrons. Its valancy is -2. It means can share share and it can gain 2 electron to get stability.

Hence, The element oxygen has 7 valence electrons.

the answer is definitely c.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.