write 5-6 differences between isobars and isotopes in a tabular form .

how to find valency of an element?

what were the drawbacks of thomson model of atom

Calculate the number of molecules in 8g of Oxygen ?

the following data represents the distribution of electrons ,protons and neutrons in atoms of four elements A, B, C, D.

ELEMENTS PROTONS NEUTRONS ELECTRONS

A 19 21 19

B 17 18 17

C 17 20 17

D 18 22 18

Answer the following:

1. describe the electronic distribution in atom of element B.

2. is element B a metal or non-metal? why?

find the valency of sulphur .[atomic no.=16

what are canal rays ?

5 examples of isotopes and 5 examples of isobars

 What is the valency of copper?

1.If the number of molecules in a given sample of SO2 is 3.011 x10 ²³

Calculate the following:

a) Number of moles in the given sample

b) Mass of SO2 in the sample

c) Number of oxygen atoms in the sample

EXPLAIN THE LAW OF CONSERVATION OF MASS WITH AN EXAMPLE ?

 an ion M³⁺ contains 10 electrons and 14 neutrons.What are the atomic mass and mass number of the element M ? name the element

Compare the properties of electrons, protons and neutrons.

is it possibe for the atom of an element to have one electron one proton and no neutron?if so name the element

what are the application of isotopes

What are the drawbacks of Rutherfords atomic model?

what is the difference between sodium ion and sodium atom ?

Q.1. How many molecules are present in

(a) 9 grams of water

(b) 17 grams of amonia

Q.2. Calculate the number of moles in 17 grams of H₂O₂

Q.3. Show that 12 grams of carbon-12 contains 6.023 x 10²³ atoms of ¹²C

Q.4. What is the mass of one atom of hydrogen ?

Q.5. How many moles of Mg atoms are there in 100 grams of magnesium ?

Q.6. Neon gas consist of single atoms. What mass of neon contains 6.023 x 10²³ atoms ?

what is the atomicity of ammonia

difference between electrons protons and neutrons...also find the relation between the three

1. Calculate the molecular mass of CaCO₃ at mass Ca=40u,C=12u,O=16u
2. Verify by calculating that

• 5 moles of CO₂ and 5 moles of H₂O do have the same mass.
• 240g of calcium and 240g of magnisium element have a mole ratio of 5:3.at mass H=1u ,Ca=40u,Mg=24u

 Who discovered proton? Golstein or Rutherford?

• 1.  Projected area fraction of atoms on a plane
• 2.  Distance between two adjacent atoms
• 3.  Volume fraction of atoms in cell
• 4.  None

Q1 Tabulate name of elements,their latin names and symbols.

how many molecules are present in

a) 9g of water

b) 17g of ammonium

1. define mole
2. how is it related to avogadro constant , relative mass and molecular mass
3. what is the no. of molecules in 0.25 moles of oxygen . avogadro's no =6.022*10 power is 23

explain the rutherford's gold foil experiment with the help of diagram?

what is electrovalency and covalency

(a) What are isobars? Give one example. (b) Write any two uses of isotopes

Write two differences between isobars and isotopes.

why is the valency of phosphorus 3 & 5 both ?

How to learn the 30 elements of modern periodic table Quickly?

• 1.  a/2
• 2.  a
• 3.  a/(4/√3)
• 4.  a/(4/√2)

Calculate the no. of atoms of each element persent in 9.8 g of sulphuric acid, H₂SO₄. (H=1, S=32, O=16)

identify the isotopes out of A,B,C and D?

³³A₁₇ , ⁴⁰B₂₀ , ³⁷C₁₇ , ³⁸D₁₉

what r the rules of distribution of electrons in different shells of an atom.Pls give me all rules of higher classes also.

the description of atomic particles of two elements X and Y is given below:

X Y

protons 8 8

neutrons 8 9

electrons 8 8

i) what is the atomic number of Y?

ii) what is the mass number of X?

iii) what is the relation between X and Y?

iv) which element/elements do they represent?

v) write the electronic configuration of X.

vi) write the cation/anion formed by the element.

What is the valency of Aluminium whose atomic number is 13 ? Give reason.

what is the valency of gold, silver and lead and can you explai how we can find the valency of a compound like NH₄, SO₂, CO₃ etc.

discrete orbits are also known as_____

what are properties of anode rays x rays cathode rays and alpha particles

• 1.  1
• 2.  3
• 3.  2
• 4.  4

 wht r d drawbacks of bohr's model of an atom??

An element A forms an oxide A₂O₃ the valency of A

 Give 6 examples of isobars .........

valency of carbon in CH4 , C2H6 , C2H4 , C2H2 ???

Suppose that there were two isotopes of Sodium. 28% of the naturally occurring sodium atoms had a mass of 22, and 72% atoms had a mass of 23. What would the average atomic weight of sodium be?

 discovery of electrons

Calculate the percentage of

[a] Water of crystallization in CuSO4.5H2O

[B] Potassium in K2CO3

[c] Oxygen in 22g of CO2

[D] Hydrogen in 36g of water

State 3 characteristics of canal rays.

what would be the electronic configuration fm Na⁺,Al³⁺,O^2-,Cl^-

​Calculate number of neutrons present in 12 × 10²⁵ atoms of oxygen (₈O¹⁷). (Given N_A = 6 × 10²³ atoms)

(A) 1800 (B) 1600 (C) 1800 N_A (D) 3200 N_A

 State two main postulates of Thomson model of an atom

 applications and examples of isotopes an isobars ?

How many atoms are present in SO4 raised to 2- ion and NH4+ ion???

 Q :If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom and (ii) what is the charge on the atom?

what is difference between Isotopes, Isobars and Isotones

give the symbol, relative charge and mass of the three sub atomic particles.

give the atomic masses of important element for class 9

You are given an element ₇X¹⁴.Find out.

a.1.number of protons,electronsneutrons in X

a.2.valency of X

a.3.electronic configuration of X.

b.If Bromine atom is available in the form of, say two isotopes

₃₅BR⁷⁹ (49.7%) ₃₅BR⁸² (50.3%).

an element X forms an oxide with formula X₂O₃

state the valency of X,write the formula of chloride of X and sulphate of X.

difference between isotope and isobars

The electronic configuration of potassium(K) is 2,8,8,1 instead of 2,8,9 thogh the M shell can accommodate up to 18 electrons. Explain

List any three distinguishing features between the models of an atom proposed by J.J
Thomson and Ernest Rutherford.

who discovered the proton? E. goldstein or rutherford?

If Z = 3, what would be the valency of the element? Also, name the element.

Find the number of electrons, protons and neutrons possessed by the alpha particles (4/2 He++) used in the gold leaf experiment,

write three significant features of Bohr's model of an atom.

Name three feature of rutherford's model

• 1.  (100)
• 2.  (110)
• 3.  (111)
• 4.  None

what are cathode rays and anode rays?