Choose the correct options and fill in the blanks by the correct word.
An_________ (atom /element) is a pure substance which cannot be split into anything simpler by chemical means.

Explanation

To solve the question, we need to determine the correct word to fill in the blank: "An _________ is a pure substance which cannot be split into anything simpler by chemical means."

### Step-by-Step Solution:

1. **Understanding the Terms**:
- An **atom** is the smallest unit of an element, consisting of protons, neutrons, and electrons.
- An **element** is a pure substance that consists of only one type of atom and cannot be broken down into simpler substances by chemical means.

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