Question:
What are ?-particles?
Answer:
α-particles are doubly-charged helium ions with 4 units of mass. These are produced from radioactive sources like Radium or Polonium.
42He → He2+ + 2e-
Structure of the Atom
Q 1.
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 2.
Who discovered protons?
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.
Fill in the blanks :
Anode rays are also called ___________.
Q 7.
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 8.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 9.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 10.
How many times is a proton heavier than an electron ?
Q 11.
What is the absolute mass and charge of a proton ?
Q 12.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 13.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 14.
What is ionization energy?
Q 15.
What is mass number?
Q 16.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 17.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 18.
What is a neutron ? State its relative mass and charge.
Q 19.
Write a short note on Nucleus.
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.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 23.
What are ?-particles?
Q 24.
How does an electron differ from a neutron ?
Q 25.
Who discovered electrons?
Q 26.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 27.
Name the radioactive isotope which is used in the treatment of cancer.
Q 28.
State the location of electrons, protons and neutrons in an atom.
Q 29.
State whether the following statement is true or false :
Radioactive isotope of iodine is used for making the medicine called tincture iodine.
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.
What are canal rays?
Q 32.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 33.
What are isobars ? Explain with an example.
Q 34.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 35.
What is the maximum number of electrons that can go into the N shell of an atom ?
Q 36.
(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 37.
What name is given to those atoms which contain the same number of protons and electrons but different number of neutrons ?
Q 38.
(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 39.
What is Atomic Number? Who coined this term?
Q 40.
Fill in the blanks :
The total number of protons and neutrons in the nucleus of an atom is called its __________.
Q 41.
Given that the percentage abundance of the isotope
Ne, is 90% and that of the isotope
Ne, is 10%,calculate the average atomic mass of neon.
Q 42.
Fill in the blanks :
________ rays are negatively charged.
Q 43.
Fill in the blanks :
The fundamental particle not present in hydrogen atom is __________.
Q 44.
What is the maximum number of electrons which can be accommodated in the K shell of an atom
Q 45.
Name the particles which actually determine the mass of an atom.
Q 46.
Which part of an atom was discovered by Rutherford's alpha particle scattering experiment ?
Q 47.
What is a proton ? How does it differ from a neutron ?
Q 48.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 49.
Give one example of a radioactive isotope which is used as a fuel in the reactors of nuclear power plants.
Q 50.
State one use of radioactive isotopes in industry.
