How many atoms of each element are in the following?
a. ch4
b. mg3(po4)2

a). 5 atoms

b). 13 atoms

Explanation:

Atoms: It is the smallest unit of the element.

Atomicity : Total number of atoms present in the molecule. For e.g each molecule of gas contain 2 atoms of nitrogen.

= 1 atom of C + 4 atoms of H

                                 = 5 atoms

= 3 atoms of Mg + (1 atom of P + 4 atoms of O )

= 3 +5

= 3 + 10

= 13 atoms

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.