Periodic Classification Of Elements Book Back Questions 10th Science Lesson 8

10th Science Lesson 8

8] Periodic Classification Of Elements

Book Back Questions with Answer and Do You Know Box Content

Do You Know?

Noble gases show no tendency to accept electrons because the outer s and p orbitals of noble gases are completely filled. No more electrons can be added to them and hence their electron affinities are zero.

Extraction of metal from metal oxide can be categorized into three types:

More reactive metals	Medium reactive metals	Less reactive metals
Na, K, Ca, Mg, Al	Zn, Fe, Pb, Cu	Ag, Hg
Electrolytic reduction of metal oxide into metal	Chemical reduction of metal oxide into metal using coke	Thermal decomposition of metal oxide into metal

Dilute or concentrated nitric acid does not attack aluminium, but it renders aluminium passive due to the formation of an oxide film on its surface.

Choose the best answers:

1. The number of periods and groups in the periodic table are _____________

(a) 6, 16

(b) 7, 17

(c) 8, 18

(d) 7, 18

2. The basis of modern periodic law is ____________

(a) Atomic number

(b) Atomic mass

(c) Isotopic mass

(d) Number of neutrons

3. _________________ group contains the member of halogen family.

(a) 17^th

(b) 15^th

(c) 18^th

(d) 16^th

4. _________ is a relative periodic property.

(a) Atomic radii

(b) Ionic radii

(c) Electron affinity

(d) Electronegativity

5. Chemical formula of rust is _____________

(a) FeO.xH₂O

(b) FeO₄.xH₂O

(c) Fe₂O₃.xH₂O

(d) FeO

6. In the alumina thermic process the role of Al is ______________

(a) Oxidizing agent

(b) Reducing agent

(c) Hydrogenating agent

(d) Sulphurising agent

7. The process of coating the surface of metal with a thin layer of zinc is called _______________

(a) Painting

(b) Thinning

(c) Galvanization

(d) Electroplating

8. Which of the following have inert gases 2 electrons in the outermost shell?

(a) He

(b) Ne

(c) Ar

(d) Kr

9. Neon shows zero electron affinity due to ___________________

(a) Stable arrangement of neutrons

(b) Stable configuration of electrons

(c) Reduced size

(d) Increased density

10. _______________ is an important metal to form amalgam.

(a) Ag

(b) Hg

(c) Mg

(d) Al

Fill in the blanks:

1. If the electronegativity difference between two bonded atoms in a molecule is greater than 1.7, the nature of bonding is ________________

1. atomic
2. ionic
3. electronic
4. none of the above

2. ___________ is the longest period in the periodical table.

1. 4^th
2. 5^th
3. 6^th
4. 7^th

3. ______________ forms the basis of modern periodic table.

1. Mass number
2. Atomic number
3. Avagardo’s number
4. None of the above

4. If the distance between two Cl atoms in Cl₂ molecule is 1.98 Å, then the radius of Cl atom is ____________

1. 0.96 Å
2. 0.97 Å
3. 0.98 Å
4. 0.99 Å

5. Among the given species A^–, A⁺, and A, the smallest one in size is ______________

1. A^–
2. A
3. A⁺
4. None of the above

6. The scientist who propounded the modern periodic law is ____________

1. Avagardo
2. Dalton
3. Dimitri Mendeleev
4. None of the above

7. Across the period, ionic radii _________________ (increased, decreases).

1. Increases
2. Decreases
3. Remains the same
4. None of the above

8. __________________ and _______________ are called inner transition elements.

1. Lanthanides, Actinides
2. Chalcogens, Halogens
3. Alkalines, Alakalis
4. None of the above

9. The chief ore of Aluminium is ______________

1. Ferrous
2. Lithium
3. Bauxite
4. None of the above

10. The chemical name of trust is ___________

1. Ferric oxide
2. Hydrated ferric oxide
3. Hydrated Ferrous oxide
4. None of the above

Match the following:

1. Galvanisation – noble gas elements

2. Calcination – coating with Zn

3. Redox reaction – silver-tin amalgam

4. Dental filling – alumina thermic process

5. Group 18 elements – heating in the absence of air

State true or false. If false, correct the statement:

1. Moseley’s periodic table is based on atomic mass.

2. Ionic radius increases across the period from left to right.

3. All ores are minerals; but all minerals cannot be called as ores;

4. Al wires are used as electric cables due to their silvery white colour.

5. An alloy is a heterogenous mixture of metals.

Consider the statements given below and choose the correct option:

Answer the following questions using the data given below:

i) A and R are correct, R explains the A.

ii) A is correct, R is wrong.

iii) A is wrong, R is correct

iv) A and R are correct, R doesn’t explain A.

1. Assertion: The nature of bond in HF molecule is ionic.

Reason: The electronegativity difference between H and F is 1.9.

2. Assertion: Magnesium is used to protect steel from rusting.

Reason: Magnesium is more reactive than iron.

3. Assertion: An uncleaned copper vessel is covered with greenish layer.

Reason: Copper is not attacked by alkali.

Answers:

Choose the best answer:

1.7,18 2. Atomic number 3. 17^th 4. Ionic Radii 5. Fe₂O₃. xH₂O 6.

1. Reducing agent 7. Galvanization 8. He

9. Stable configuration of electrons

1. 10.Hg

Fill in the blanks:

1. ionic 2. 6th (sixth) period 3. Atomic number 4. 0.99 Å 5. A⁺ 5.

1. Dimitri Mendeleev 7. Decreases 8. Lanthanides, Actinides

9.bauxite 10. hydrated ferric oxide

Match the following:

1. coating with Zn 2. heating in the absence of air 3. alumina thermic process 4. silver-tin amalgam

5. noble gas elements

True or False:

1.False – Moseley’s periodic table is based on atomic number.

2.True

3.True

4.False – Aluminium wires are used as electric cables because it is a good conductor of heat and electricity.

5.False – An alloy is a homogeneous mixture of metals.

Reason and Assertion:

1. A and R are correct, R explains the A
2. A and R are correct, R explains the A
3. A and R are correct, R doesn’t explain A.