Question:
What are isobars ? Explain with an example.
Answer:
The atoms of different elements having different atomic numbers may have the same mass number. Such atoms are called isobars.
Structure of the Atom
Q 1.
Who discovered protons?
Q 2.
What do you think would be the observation if the ?-particle scattering experiment is carried out using a foil of a metal other than gold?
Q 3.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 4.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 5.
Describe briefly Thomson's model of an atom.
Q 6.
What is the relationship between an atom containing 11 protons, 11 electrons and 11 neutrons, and another atom containing 11 protons, 11 electrons and 12 neutrons ?
Q 7.
Fill in the blanks :
Anode rays are also called ___________.
Q 8.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 9.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 10.
What is the absolute mass and charge of a proton ?
Q 11.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 12.
How many times is a proton heavier than an electron ?
Q 13.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 14.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 15.
What is ionization energy?
Q 16.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 17.
What is mass number?
Q 18.
Write a short note on Nucleus.
Q 19.
What is a neutron ? State its relative mass and charge.
Q 20.
Fill in the blanks :
______ are atoms of the same element, which have same number of protons but different mass numbers.
Q 21.
Fill in the blanks :
Atoms are made up of __________, ___________ and __________.
Q 22.
What are ?-particles?
Q 23.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 24.
Who discovered electrons?
Q 25.
How does an electron differ from a neutron ?
Q 26.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 27.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 28.
Name the radioactive isotope which is used in the treatment of cancer.
Q 29.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 30.
Fill in the following blanks in respect of an atom of an element :
No.of
protons | No.of
neutrons | Mass number | Atomic
number | No.of
electrons | Valency |
|---|
| 11 | 12 | ........ | ....... | ........ | ......... |
Q 31.
State the location of electrons, protons and neutrons in an atom.
Q 32.
(a) Describe the Rutherford's model of an atom. State one drawback of Rutherford's model of the atom.
(b) The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it ? What is the atomic number of the element ?
Q 33.
What name is given to those atoms which contain the same number of protons and electrons but different number of neutrons ?
Q 34.
(a) What are radioactive isotopes ? Give two examples of radioactive isotopes.
(b)Give any two uses of radioactive isotopes.
(c)An element Z contains two naturally occurring isotopes
Z and
Z. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.
Q 35.
Which part of an atom was discovered by Rutherford's alpha particle scattering experiment ?
Q 36.
State whether the following statement is true or false :
Radioactive isotope of iodine is used for making the medicine called tincture iodine.
Q 37.
(a)What are valence electrons ? Where are valence electrons situated in an atom ?
(b)What is the number of valence electrons in the atoms of an element having atomic number 13 ? Name the Valency shell of this atom.
Q 38.
What are canal rays?
Q 39.
Draw a sketch of Bohr’s model of an atom with three shells.
Q 40.
Fill in the blanks :
An atom has mass number 27 and atomic number 13. The atom has _________ electrons, _____ protons and _______ neutrons.
Q 41.
Fill in the blanks :
__________ electrons are located in the outermost shell of an atom.
Q 42.
What is the maximum number of electrons that can go into the N shell of an atom ?
Q 43.
Name the positively charged particle present in the atoms of all the element
Q 44.
What is the absolute mass and charge of an electron ?
Q 45.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 46.
Give one example of a radioactive isotope which is used as a fuel in the reactors of nuclear power plants.
Q 47.
Complete the following statements :
(a) Magnesium has 2 valence electrons in the......... shell.
(b)The valency of nitrogen in N2 molecule is........
(c)Isotopes have different mass numbers because their nuclei contain different number of........
(d) Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass numbers are called............
Q 48.
What valencies will be shown by the elements A, B, C, D and E having atomic numbers 2, 4, 8, 10, and 13 respectively.
Q 49.
Which of the following are isotopes and which are isobars ?
Argon, Deuterium, Calcium, Tritium, Protium
Q 50.
What are isobars ? Explain with an example.
