Element

Q.

Classify the following into elements, compounds and mixtures. (a) Sodium (b) Soil (c) Sugar solution (d) Silver (e) Calcium carbonate (f) Tin (g) Silicon (h) Coal (i) Air (j) Soap (k) Methane (l) Carbon dioxide (m) Blood.

Q.

Give an example of a compound, element, and mixture.

Q.

State main characteristics of element.

Q.

Classify the following as element, mixture or compound:

blood

Q.

What is water made up of ?

Q.

If water molecule contains two hydrogen and one oxygen atoms. Then why humans are not making it in laboratories?

Q. Air is an element.

1. False
2. True

Q.

The constituents of a compound can be separated by _______ (physical/chemical) methods.

Q.

Write the formulae of the following compounds:

Barium sulphate

Q.

Name two elements that exist in the form of molecules.

Q.

Define the following term :

Atom

Q.

Elements are made up of ______ kind of atoms.

1. only one

2. different

3. two

4. dissimilar

Q. An element has similar types of atoms.

1. True
2. False

Q.

All matter is made of small indivisible particles called atoms. Atoms, however, do not have an independent existence, in general. They generally exist in combination with other atoms in the form of molecules or ions. Molecules are thus, the smallest particles of various substances (elements or compounds) which have an independent existence. The number of atoms present in one molecule is called atomicity.

Answer the following questions after reading the paragraph.

(1) Write any specific name given the molecule containing the same atoms.

(2) Name two elements whose atoms exist independently.

(3) Atomicity of a molecule of sulphuric acid is

(a) 8 (b) 7 (c) 6 (d) 4

(4) Which of the following elements exhibits the atomicity of eight?

(a) Phosphorus (b) Sulphur (c) Boron (d) Oxygen

Q.

Write the chemical formula of the following chemical compounds;

(C) Potassium chlorate

Q.

(a) Define element.

(b) State main characteristics of element

Q.

Fill in the blank:

• A compound can be broken into its ______ by chemical process.

Q.

Differentiate between the following: Atoms and molecules.

Q. Which of the following is an element?

1. Salt
2. Sugar
3. Hydrogen
4. Water

Q.

_____ have no fixed properties.

Q.

Molecules are made up of _______.

1. solids
2. atoms
3. strings
4. particles

Q.

How is an atom different from an element? How many elements are there?

Q.

Define atoms.

Q. Which of the following is an element?

1. Sugar
2. Water
3. Copper
4. Salt

Q.

Compounds can be separated into its elements.

1. True

2. False

Q.

Air is a mixture.