Fill in the blank by using correct word/term given in the bracket and rewrite the complete sentence in your notebook.
The atoms combine to have __________ electrons in their valence shells is the octet rule. (eight/eighteen)

Explanation

To solve the question, we need to fill in the blank with the correct term from the options given in the bracket. The sentence is: "The atoms combine to have __________ electrons in their valence shells is the octet rule."

### Step-by-Step Solution:

1. **Understand the Octet Rule**: The octet rule is a fundamental principle in chemistry that states that atoms tend to combine in such a way that they each have eight electrons in their valence shell, achieving a stable electron configuration.

2. **Identify the Options**: The options provided in the bracket are "eight" and "eighteen."

...