Samacheer Kalvi solutions for Science - Term 1 [English] Class 7 TN Board chapter 3 - Matter Around Us [Latest edition]

Which one of the following is an example for a metal?

Oxygen, hydrogen, and sulphur are examples for 

Which of the following is a short and scientific way of representing one molecule of an element or compound?

The metal which is liquid at room temperature is ______.

An element which is always lustrous, malleable and ductile is ______.

The smallest particle of matter that can exist by itself is ______.

A compound containing one atom of carbon and two atoms of oxygen is ______.

______ is the only non-metal which conducts electricity.

Elements are made up of______ kinds of atoms.

______ of some elements are derived from Latin or Greek names of the elements.

There are ______ number of known elements.

Elements are the______ form of pure substances.

The first letter of an element is always written in ______ letter.

Molecule containing more than three atoms are known as ______.

______ is the most abundant gas in the atmosphere.

Mercury: Liquid at room temperature:: Oxygen: ______.

Non-metal conducting electricity :______ :: Metal conducting electricity : Copper

Elements : Combine to form compounds :: Compounds : ______.

Atoms: Fundamental particle of an element::______ : Fundamental particles of a compound.

State true of false. If false, give the correct statement.

Two different elements may have similar atoms.

State true of false. If false, give the correct statement.

Compounds and elements are pure substances.

State true of false. If false, give the correct statement.

Atoms cannot exist alone. They can only exist as groups called molecules.

State true of false. If false, give the correct statement.

NaCl represents one molecule of sodium chloride.

State true of false. If false, give the correct statement.

Argon is mono atomic gas.

Write the chemical formula and name the elements present in the following compounds.

1. Sodium chloride
2. Potassium hydroxide
3. Carbon dioxide
4. Calcium oxide
5. Sulphur dioxide

Classify the following molecules as the molecules of element or compound

1.
2.
3.
4.

What do you understand by chemical formula of a compound? What is its significance?

Define the following term with an example.

Element 

Define the following term with an example.

Compound

Define the following term with an example.

Metal

Define the following term with an example.

Non-metal

Define the following term with an example.

Metalloid

Write the symbols for the following elements and classify them as solid, liquid and gas. Aluminum, Carbon, Chlorine, Mercury, Hydrogen and Helium

Classify the following as metals, non-metals and metalloids.

Sodium, Bismuth, Silver, Nitrogen, Silicon, Carbon, Chlorine, Iron, Copper

Classify the following as elements and compounds.

Water, Common salt, Sugar, Carbon dioxide, Iodine and Lithium

Write the chemical formula for the following elements.

1. Hydrogen
2. Nitrogen
3. Ozone
4. Sulphur

What are elements? What are they made of? 

Give two example of elements.

Define molecule.

What are compounds? Give two examples.

Give an example for the elements derived from their Latin names.

What is atomicity of elements?

Calculate the atomicity of H₂SO₄

Differentiate metals and non-metals.

Explain the characteristics of compounds

Describe the different ways in which we can write the symbols of elements. Give appropriate examples.

Differentiate between elements and compounds.

Explain the characteristics of compounds

Compare the properties of metals and nonmetals. Give three examples for each.

Write down the properties of metalloids.

Rewrite the given sentence in correct form.

Elements contain two or more kind of atoms and compounds contain only one kind of atom.

Higher Order Thinking Skills.

List out the metals, non-metals and metalloids which you use in your house, schools. Compare their properties.

Higher Order Thinking Skills.

What changes take place in the movement and arrangement of particles during heating process?

Higher Order Thinking Skills.

In the diagram given below, the circle, square and triangle represent the atoms of different elements.

Identify all combinations that represent

1. molecule of a compound 
2. molecule of an element consisting of two atoms
3. molecule of an element consisting of three atoms

Higher Order Thinking Skills.

Aakash noticed that the metal latch on gate was difficult to open during hot sunny days. However, it was not difficult to open the same latch at night. Aakash observed that the latch and the gate are exposed to the sun during day time.

1. Formulate a hypothesis based on the information provided.
2. Briefly state how you would test the hypothesis.

Assertion: Oxygen is a compound.

Reason: Oxygen cannot be broken down into anything simpler.

Assertion: Hydrogen is an element.

Reason: Hydrogen cannot be broken down into anything simpler.

Assertion: Air is a compound.

Reason: Air consists of carbon dioxide.

Assertion: Air is a mixture of elements only.

Reason: Only nitrogen, oxygen and neon gases exist in air.

Assertion: Mercury is solid in room temperature.

Reason: Mercury is a non-metal.