Which of the statements correctly describes the reactivity of noble gases, according to the octet rule?
They have eight electrons in their valence shell, so noble gases are very unreactive.
They have eight electrons in their valence shell, so noble gases are very reactive.
They have one electron in their valence shell, so noble gases are very reactive.
They have one electron in their valence shell, so noble gases are very unreactive
I agree; however, look at Damon's answer and note that He is a noble gas, too, but doesn't have eight electrons in the outside shell. Also, note that some of the noble gases do form compounds
The correct statement is: They have eight electrons in their valence shell, so noble gases are very unreactive.
The correct statement that describes the reactivity of noble gases, according to the octet rule, is:
They have eight electrons in their valence shell, so noble gases are very unreactive.
To understand why this is the correct statement, we need to understand the octet rule. The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration with eight electrons in their outermost (valence) shell.
Noble gases, such as helium, neon, argon, krypton, and xenon, have a full valence shell with eight electrons, except for helium which has only two electrons in its valence shell. This full valence shell makes them highly stable and less likely to interact or react with other atoms to gain or lose electrons.
Therefore, since noble gases have a complete octet in their valence shell, they are considered unreactive or inert. They rarely form compounds under normal conditions and are known for their low reactivity.
If the outer shell is full of eight electrons it is very hard to either remove on or add one or even share so such an element is called "noble". Neon, Argon etc have full outer shells with eight.
The innermost shell only holds two electrons so Helium is usually also called a noble gas because it is not reactive for the same reason of a full outer electron shell.