Asked/Added Questions From NCERT:


Question 1. Asked on :01 March 2019:03:37:26 PM

 Justify the statement that the elements having atomic number 3 and 11 will belong to the same group of periodic table.

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Himanshi Verma

Two elements are X  with atomic number 11 ---- Sodium

Y has less metallic character because metallic character decreases in a period from left to right.

2. .Calculate the valency of each element.

Element X --- electronic configuration : 1s22s22p63s1

so valency is one.

Element Y electronic configuration : 1s22s22p63s23p3

Velency is three.

3 "Element ‘X’ is bigger than ‘Y’ in terms of atomic size. Is the statement true, justify? "

Its true . Because atomic size decreases over period due to increase in nuclear Charge.

-Answered by Himanshi Verma On 22 March 2019:05:03:50 PM


Question 2. Asked on :19 February 2019:12:41:37 PM

Who discovered cell first ?

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Himanshi Verma

 Robert Hook in 1665.

-Answered by Himanshi Verma On 24 February 2019:05:04:19 PM


Question 3. Asked on :18 January 2019:05:19:11 PM

 Hydrogen and Oxygen combine in the ratio of 1:8 by mass to form water. What mass of Oxygen Gas would be required to react completely with 3gm of hydrogen gas ?

-Added by khushi chauhan Science » Atom And Molecules

Answer:

Himanshi Verma

 Since, the ration by which oxygen and hydrogen combine to give water is 1:8.

We can take it as "1g of hydrogen combines with 8g oxygen to give water''

So, 3g of hydrogen will combine with 3×8=24g of oxygen to give water.

-Answered by Himanshi Verma On 20 January 2019:04:29:23 PM


Question 4. Asked on :18 January 2019:05:18:45 PM

 What is Atomicity?


-Added by khushi chauhan Science » Atom And Molecules

Answer:

Himanshi Verma

 The number of atom present in one molecule of an element is called Atomicity.

-Answered by Himanshi Verma On 20 January 2019:04:29:11 PM


Question 5. Asked on :14 January 2019:05:36:38 PM

 What is the full name of J.J Thomson?

-Added by Himanshi Verma Science » Atom And Molecules

Answer:

Prince Rawat

 Joseph john thomson.

-Answered by Prince Rawat On 15 January 2019:10:20:32 AM


Question 6. Asked on :13 January 2019:04:45:46 PM

What is the atomicity of Iodine?

-Added by Himanshi Verma Science » Atom And Molecules

Answer:

Akki chauhan

 The atomicity of iodine is Diatomic. 

-Answered by Akki chauhan On 14 January 2019:09:06:14 AM


Question 7. Asked on :12 January 2019:11:07:42 AM

 Define the term mass number giving an example.

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Akki chauhan

  Mass number is the sum of neutrons and protons. For example no. of protons in hydrogen is 1 and no. of neutrons is 0. So, 0+1=1, the mass of hydrogen is 1.

-Answered by Akki chauhan On 14 January 2019:09:59:13 AM


Question 8. Asked on :12 January 2019:11:05:19 AM

What is the nucleus of the atom?

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Akki chauhan

   Almost all of the mass in an atom is made up from the protons and neutrons in the nucleus with a very small contribution from the orbiting electronsNeutrons have no charge and protons are positively charged. Because the nucleus is only made up of protons and neutrons it is positively charged.

-Answered by Akki chauhan On 15 January 2019:09:46:08 AM


Question 9. Asked on :12 January 2019:11:02:38 AM

 How is the valency of an atom related to its electronic configuration?

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Akki chauhan

  An atom according to its atomic number  arranges the electrons in the shells and when all electrons  are arranged then the electron (valence electrons) in the valence shell loses or gains electrons to complete octet and by doing so it gains negative or positive valency.

-Answered by Akki chauhan On 15 January 2019:09:45:48 AM


Question 10. Asked on :12 January 2019:11:01:34 AM

 Define electron, proton, and neutron.

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Akki chauhan

  Electron=A Electron is a subatomic particle. Electrons have a negative electric charge. It is discovered by J.J Thomson.

Proton= Proton is also a Subatomic Particle which symbol is p with a positive charge. It is discovered by E.Rutherford. 

Neutrons= Neutron is also a subatomic particle which symbol is n with no electric charge and a mass slightly larger than that of proton. 

-Answered by Akki chauhan On 15 January 2019:09:45:31 AM


Question 11. Asked on :12 January 2019:10:59:35 AM

Write drawbacks of Rutherford ? 

-Added by Akki chauhan Science » Atom And Molecules

Answer:

Himanshi Verma

 Drawbacks of Rutherford’s model of atom

  • Rutherford proposed that electrons revolve at a high speed in circular orbits around the positively charged nucleus. When a charged particle i. e. electron revolves around positively charge nucleus, it needs to be accelerated so as to keep it moving in circular orbits. However, according to electromagnetic theory, whenever a charged particle such as an electron is accelerated around another charged center ( nucleus ) which are under force of attraction, there will be continuous radiation of energy. This loss of energy would slow down the speed of the electron. This would reduce the radius of the electron–orbit. Eventually the electron would fall into the nucleus. The result would be that the atom would collapse. But this does not happen. Thus Rutherford’s atom could not explain the stability of the atom. Failure of Rutherford’s model i.e. reduction of radius of orbit is shown below.
  • Rutherford proposed that electrons revolve around the nucleus in the fixed orbits. However, he did not specify the orbits and the number of electrons in each orbit.

-Answered by Himanshi Verma On 02 February 2019:01:52:05 PM


 

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