Parameters Of An Atom Free Doubts and Solutions
CBSE - IX - Chemistry - Structure of the Atom
Sir how find atomic mass in element
CBSE - IX - Chemistry - Structure of the Atom
The fuel used in neuclear power plants is a) U-235 or b) Enriched U-235
CBSE - IX - Chemistry - Structure of the Atom
The sum of protons, electron and nutrons in heaviest isotope of hydrogen?
CBSE - IX - Chemistry - Structure of the Atom
The number of nucleons in D2 molecule??
CBSE - IX - Chemistry - Structure of the Atom
Q the half line of a radioactive isotope is 1.5 hrs. The mass of it that remains undecayed after 6 hours if the initial mass of spectrum of the isotope of 32g is
CBSE - IX - Chemistry - Structure of the Atom
Helium atom has two electrons in its valence shell but its valency is zero. Explain.
Helium atom has two electrons in its valence shell but its valency is zero. Explain.
CBSE - IX - Chemistry - Structure of the Atom
Explain isotopes and isobars with the help of suitable examples.
CBSE - IX - Chemistry - Structure of the Atom
Explain atomic number and atomic mass number.
CBSE - IX - Chemistry - Structure of the Atom
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.
CBSE - IX - Chemistry - Structure of the Atom
(a) How are electrons arranged around the nucleus in an atom.
(b) If an atom of an element has atomic number 11 and mass number 23, find the number of protons, electrons and neutrons in its atoms.
OR
(a) The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes 
in the sample?
(b) Complete the following table.
in the sample?|
Elements |
Atomic Number |
Mass Number |
Protons |
Neutrons |
Electrons |
|
A |
11 |
- |
- |
12 |
- |
|
B |
- |
35 |
- |
- |
17 |
CBSE - IX - Chemistry - Structure of the Atom
(a) 
are symbols of two isotopes of Magnesium. Compare atoms of these isotopes with respect to
(i)Composition of their Nuclei
(ii)Electronic configuration and valency
(b)Give the reason why two isotopes of magnesium have different mass numbers.
are symbols of two isotopes of Magnesium. Compare atoms of these isotopes with respect toCBSE - IX - Chemistry - Structure of the Atom
Composition of the nuclei of two atomic species 'X' and 'Y' are given below. X Y Protons 8 8 Neutrons 8 10 (a) Write the mass number of X and Y respectively. (b) Write the electronic configuration of the element 'X'. (c) Is there any similarity between X and Y? How are they related to each other.
CBSE - IX - Chemistry - Structure of the Atom
The average atomic mass of a sample of an element X is 35.5 u. What are the percentages of isotopes 
and in the sample?
and in the sample?CBSE - IX - Chemistry - Structure of the Atom
The atomic number of Chlorine is 17 and mass number is 35.
(a) What would be the electronic configuration of negatively charged chlorine ion, Cl-?
(b) What would be the atomic number and mass number of Cl-?
(c) Define valency and calculate the valency of Cl-.
OR
(a) Consider the atom 
.
(i) What does the figures 5 and 10 indicate?
(ii) How many number of electrons does this element contain?
(iii) The relative atomic mass of Boron is 10.8 u. Calculate the percentage of its isotopes and 
, occurring in nature.
. and , occurring in nature.CBSE - IX - Chemistry - Structure of the Atom
Sulphur dioxide (SO2) is a colourless pungent smelling gas and is a major air pollutant. (a) Write the electronic configuration of its constituent elements: Sulphur and Oxygen. (b) Write valency of Sulphur and Oxygen. (c) Are sulphur and oxygen isotopes of same element? Explain your answer.
CBSE - IX - Chemistry - Structure of the Atom
(a) Why do the inert gases like neon and argon have zero valency?
(b) The atomic number of sodium is 11 and oxygen is 8. Predict their valencies.
(c) Draw the atomic structure of sulphur 
.
(d) State the difference between a proton and an electron on the basis of their location.
(e) Give one use of an isotope of cobalt and one use of an isotope of iodine.
OR
(a) During radioactive disintegration, an atom gets converted into another atom whose mass number remains the same but atomic number increases by one. Will the new atom formed be an isobar or isotope of the parent atom?
(b) Which is heavier: a proton or an electron and how many times?
(c) How many electrons are present in the outer shell of the atom of a noble gas other than helium?
(d) Write the drawbacks of Rutherford's model.
.CBSE - IX - Chemistry - Structure of the Atom
(a) Chlorine occurs in nature in two isotopic forms with masses 35 u and 37 u in the ratio of 3:1. Calculate the average atomic mass of chlorine atom on the basis of this data. (b) Give two uses of isotopes. (c) Illustrate any two observations of Rutherford's model. OR(a) Explain why elements have fractional atomic masses.(b)What are nucleons?(c) Helium atom has atomic mass 4 and has 2 protons in its nucleus. How many neutrons does it have?
CBSE - IX - Chemistry - Structure of the Atom
What are isobars? Explain with the example.
CBSE - IX - Chemistry - Structure of the Atom
(a) In Rutherford's experiment, how was it shown that an atom has a lot of empty space within it?
(b) Why is the nucleus of an atom positively charged?
(c) Calculate the valency of chlorine, sulphur and magnesium.
Atomic number of Chlorine = 17, sulphur = 16, magnesium = 12
OR
(a) Oxygen has three isotopes of atomic masses 16, 17 and 18 respectively. Explain the following:
(i) They have same chemical properties.
(ii) They are all electrically neutral.
(iii) Name the isotopes of hydrogen.
(iv) Give one point of similarity and one point of difference between isotopes 
.
. CBSE - IX - Chemistry - Structure of the Atom
(a) Write the electronic configuration of elements with atomic number 11 and 19. (b) Write the three observations of Rutherford's α-particle scattering experiment. OR (a) Write three points of difference between isotopes and isobars. (b) Write the maximum number of electrons that can be accommodated in the K shell. (c) Why do atoms combine with one another?
CBSE - IX - Chemistry - Structure of the Atom
(a) Can electrons be arranged in second shell or L shell without filling electrons in first shell or K shell?
(b) The atom of an element X is written as 
.
(i) What does the figure 13 indicate?
(ii) What does the figure 27 indicate?
(iii) What is the number of protons in the X?
(iv) What is the number of electrons in X?
OR
Give reasons for the following:
(i) Argon and calcium are called isobars.
(i) Helium and neon have zero valency.
(iii) An atom is neutral.
(iv) Nucleus is positively charged.
(v) Isotopes have similar chemical properties.
.CBSE - IX - Chemistry - Structure of the Atom
How is the following pair of atom related?
CBSE - IX - Chemistry - Structure of the Atom
(i) Why is large part of the atom neglected when calculating the mass of the atom?(ii) Give reason why atoms combine with each other.(iii) In the notation of an atom, how are the atomic number, mass number, and symbol of the element written?
CBSE - IX - Chemistry - Structure of the Atom
What is the electronic configuration of isotopes of chlorine and isobars of calcium and argon?
CBSE - IX - Chemistry - Structure of the Atom
State the relationship between the atoms given below. Define the term used for this relationship. Write one characteristic feature of such atoms.
