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Tn 9th Science Unit 12 Assignment Answers EM

radangfx September 29, 2021

Tn 9th Science Unit 12 Assignment Answers EM : Here is the full assignment answer key for TNSCERT 9th science assignment in both print and pdf download with answers, This page gives you both English medium and we also have Tamil medium answers for 9th standard science. As per the Tamilnadu educational departments order, all school students must submit their assignments on time, But most of the students do not even start the assignment process, so we want to help those students, and here is the full assignment answer key

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Assignment

Class:9 Subject: Science

Chemistry

Unit 12 – Periodic classification of Elements

Part- A

I. 1 Mark Questions :
1) The name of 16th group elements in the periodic table is ———–

a) Oxygen (or) Chalcogen family

b) Carbon family

c) Nitrogen (or) Chalcogen family

d) Boron family

Answer:- a) Oxygen (or) Chalcogen family

2) Based on which of the following Henry Moseley demonstrated characteristics of elements.

a) X – Radiation decay

b) β-Radiation decay

c) γ – Radiation decay

d) None of the above

Answer:- a) X – Radiation decay

3) The elements present in 16th group————

a) O,S,Se, Te,Po

b) F, Cl, Br, I

c) N.P, AS, Sb

d) C, Si, Ge, Sn, Pb

Answer:- a) O,S,Se, Te,Po

4) Which block has metals, non metals and metalloid?
a) S block

b) P block

c) d block

d) f block

Answer:- b) P block

5) Inert gases belongs to ————
a) 17 Group

b) 18 Group

c) 16 Group

d) 13 Group

Answer:- b) 18 Group

Part- B

II. Short Answer:

1.Define Dobereiner’s law of triads ?

Johann Wolfgang Dobereiner arranged the elements into groups containing three elements each based on their relative, atomic masses. He called these groups as ‘traids’ also known ad Doberiner’s Triads

2.Define Metalloids

Metalloids are the elements which are having a combination of some properties of metals along with some properties of nonmetals

3.What is inert gases ?

The noble gases,also known as the inert gases and the aerogens,are the elements that belong to group 18 of the modern periodic table. The elements that belong to this group are : Helium (He) Neon (Ne) Argon (Ar)

Part- C

III. Write in detail.

Differenciate metals and non-metals

Metals

Metals are typically hard, shiny,malleable(can be made as sheet),Fusible and ductile(can be drawn into wire) with good electrical and thermal conductivity, Expect mercuty, most of the metals are solids at room temperature.

Non Metals: A nonmetal is an element that does not have the characters like hardness, shiny, Malleable, suitable and ductile. In other words, a nonmetal is an element that does not have the properties of metal. All nonmetals are arranged in p-block only. E.g, C,N,O,P,Se,Gakigeb (F,CI,Br and I) and inert gases (He to Rn)

Tn 9th Science Unit 1 Assignment Answers EM

Tamilnadu 9th standard Physics Unit 1 Measurement English medium assignment answers are available on this page – please click here