Question

1. A chemical compound always contains the same elements combined together in the
same proportion by mass. This law is ……………………………………………( 1 Mark)
2. The molecular mass of glucose ( C6H12O6) is …………………. ( 1 Mark)
3. 3 mol oxygen atom = ………………………… oxygen atoms ( 1 Mark)
4. 5 mol NH3= ………………………. Litre ( 1 Mark)
5. The orbital designation of n=2 , l =1 is …………………( 1 Mark)
6. For l=2 , m = …………………………………. ( 1 Mark)
7. Orbitals are filled in the increasing order of their energies. This principle is
…………………………….( 1 Mark)
8. State and explain law of multiple proportion ( 2 Marks)
9. What is limiting reagent? In a reaction 1 mol H2 and 2 Mol Cl2 is used to produce HCl.
Which is the limiting reagent? ( 2 Marks)
10.Write two important results observed during photoelectric effect. ( 2 Marks)
11.Which are different series of the hydrogen spectrum and give their n1 and n2( 2 Marks)
12.State Heisenberg’s uncertainty principle and give its mathematical form ( 2 Marks)
13.Explain any two quantum numbers( 2 Marks)
14.The outer most electronic configuration of nitrogen atom is 2px
12py
12pz
1
. Explain the
rule behind it ( 2 Marks)
15.An orbital can accommodate maximum two electrons . Which is the principle behind it.
State the principle . ( 2 Marks)
16. What are the important observations and conclusions made by Rutherford from his
alpha ray scattering experiment? ( 3 Marks)
17.Write any two postulates , merits and demerits of Bohr atom model? ( 4 Marks)

Answer 1

Answer:

see below

Explanation:

1) conservation of definite proportion

2) 180

3) 3× avogadro no.

4) 112L

5) 2p

6) m= -l to +l

7) afbaus principal

8) element and atoms present in different compound in its different proportion is called law of multiple proportion.

9) reagent which is present in less amount is called limiting reagent, since it consumes earlier in the reaction so rate of product formation and amount of product formation depends on limiting reagent, here H2 is limiting reagent.

10) during photoelectric effect, particle and wave nature of light is observed.

11) lyman series

balmer series

paschen series

brackett series

p fund series

humphred series

12) it is not possible to find the position and momentum of electron simultaneously,

∆X. ∆p = h/4pi m

13) principal quantum no- denoted by n, it explains about the orbit of electron, energy of electron, no of electron present in a orbital of any element, magnetic moment etc

azimuthal quantum no.= denoted by l, it explains about the sub shell of an electron.

14) hunds rule

15)