Group of atoms that gains or loses electrons is called . A. a polar ion B. a non-polar ion C. a polyatomic ion D. a common ion E. None of the Above

Option (C) is the correct answer.

Explanation:

An ion is defined as a specie which is formed when a neutral atoms tends to gain or lose an electron.

When a neutral atom gain an electron then it forms a negative ion whereas when a neutral atom tends to lose an electron then it forms a positive ion.

For example, a neutral fluorine atom on gaining an electron will form ion. And, a sodium atom on losing an electron forms ion.

When a group of atoms form ions then it tends to form polyatomic ions.

Thus, we can conclude that group of atoms that gains or loses electrons is called a polyatomic ion.

a electronegativity decreases beacuse the size of nucleus is bigger.

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.