Matter Around Us

Samacheer Book Back Questions And Answers For Science Standard 7 Term 1 “Matter Around Us“

I. Choose the appropriate answer:
1. Which of the following is an example of a metal?
(a) Iron
(b) Oxygen
(c) Helium
(d) Water

2. Oxygen, hydrogen, and sulphur are examples of which of the following?
(a) Metals
(b) Non-metals
(c) Metalloids
(d) Inert gases

3. Which of the following is a short and scientific way of representing one molecule of an element or compound?
(a) Mathematical formula
(b) Chemical formula
(c) Mathematical symbol
(d) Chemical symbol

4. The metals which is a liquid at room temperature
(a) Chlorine
(b) Sulphur
(c) Mercury
(d) Silver

5. An element which is always lustrous, malleable and ductile
(a) Non-metal
(b) Metal
(c) Metalloid
(d) Gas

II. Fill in the blanks:
1. The smallest particle of matter that can exist by itself _____.
2. A compound containing one atom of carbon and two atoms of oxygen is _____.
3. _____ is the only non-metal conducts electricity.
4. Elements are made up of _____ kinds of atoms.
5. _____of some elements are derived from Latin or Greek names of the elements.
6. There are _____ number of known elements.
7. Elements are the _____ form of pure substances.
8. The first letter of an element always written in _____ letter.
9. Molecule containing more than three atoms are known as _____.
10. _____ is the most abundant gas in the atmosphere.

Answers:
1. Atom
2. Co₂
3. Graphite
4. Same
5. Symbol
6. 118
7. Simplest
8. Capital
9. Polyatomic Molecule
10. Nitrogen

III. Fill in the blanks:
1. Mercury: liquid at room temperature:: Oxygen: _____
2. Non metal conducting electricity: _____:: Metal conducting electricity: Copper
3. Elements: combine to form compounds:: Compounds: _____
4. Atoms: fundamental particle of an element:: _____fundamental particles of a compound

Answers:
1. Gas at room temperature
2. Graphite
3. Can be split into elements
4. Elements

IV. True of False. If False, give the correct statement:
1. Two different elements may have similar atoms.
2. Compounds and elements are pure substance.
3. Atoms cannot exist alone; they can only exist as groups called molecules.
4. NaCl represents one molecule of sodium chloride.
5. Argon is mono atomic gas.

Answers:
1. True
2. True
3. True
4. True
5. True

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