Compare the following sodium atoms in terms of their neutrons and mass numbers 24Na, 23Na

Na-24 and Na-23 have the same number of atoms=11, different neutrons(13 and 12),different mass number(24 and 23)

The elements in nature have several types of isotopes

Isotopes have the same number of protons and having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

number of atoms = 11

mass number = 23

number of neutrons=23-11=12

number of atoms = 11

mass number = 24

number of neutrons=24-11=13

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.