Write the electronic configuration of calcium and potassium.​

Atomic number of potassium = 19

Therefore number of electrons = 19

Since, maximum number of electrons in outermost orbit will not be more than 8, thus the 19th electron of potassium atom will reside in 4th.

Thus, electronic configuration of potassium is

given in first pic.

Number of orbit in potassium = 4

Atomic number of calcium = 20

Therefore number of electrons = 20

Thus, electronic configuration of calcium is given in sec pic.

Number of orbit in calcium = 4

Explanation:

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substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.