Matter Around Us Pure? is the chapter 2 of Class 9 NCERT book. The Multiple Choice Question (MCQ) Question is given below for Class 9 Chapter 2 Is Matter Around Us Pure?

## Question

### A Mixture is made up of

(a) two or more elements

(b) two or more compounds

(c) both (a) and (b)

(d) none of these

Option (b) is the right answer.

## Explanation

A mixture contains two elements or two compounds or an element and a compound.

## FAQ

### What is element?

Element is known as chemical element in Chemistry. Element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed.

### What is compound?

Compound is a pure substance. It is made up of two or more elements combined chemically in a definite ratio.

### Which Element has no Nuetron?

• Hydrogen

Hydrogen has atomic number 1. It has monatomic form is the most abundant chemical substance and it has single proton and zero neutrons.

### How to find neutrons of an element?

To calculate the no of neutrons in an atom use the following formula.

Number of Neutrons = Atomic Mass- Atomic Number

Subtract the atomic number from the atomic mass.

#### Example:

Letâ€™s keep using oxygen as our example. Its atomic mass is 15.999 atomic mass units (amu) and its atomic number is 8. When we subtract 8 from 15.999, we will get 8.

The number of neutrons for an element may vary. Some elements have isotopes, which have different masses and therefore different numbers of neutrons.