Question:
Complete the following table.
| Particle | Electron | Proton | Neutron |
|---|
| (i) Symbol | __ | __ | __ |
| (ii) Nature | __ | __ | __ |
| (iii) Relative Charge | __ | __ | __ |
| (iv) Absolute Charge | __ | __ | __ |
| (v) Relative Mass | __ | __ | __ |
| (vi) Absolute Mass | __ | __ | __ |
Answer:
| Particle | Electron | Proton | Neutron |
|---|
| (i) Symbol | e- | p+ | n |
| (ii) Nature | negatively charged | Positively Charged | Neutral |
| (iii) Relative Charge | -1 | +1 | 0 |
| (iv) Absolute Charge | 1.602 × 10-19 C | 1.602 × 10-19 C | 0 |
| (v) Relative Mass | 1/1840 | 1 | 1 |
| (vi) Absolute Mass | 9.109 × 10-28 g | 1.67 ×10-24g | 1.67 × 10-24 g |
Structure of the Atom
Q 1.
Who discovered electrons?
Q 2.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 3.
Who discovered protons?
Q 4.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 5.
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 6.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 7.
How many times is a proton heavier than an electron ?
Q 8.
Write a short note on Nucleus.
Q 9.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 10.
Describe briefly Thomson's model of an atom.
Q 11.
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 12.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 13.
State one use of radioactive isotopes in medicine.
Q 14.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 15.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 16.
What is a proton ? How does it differ from a neutron ?
Q 17.
Name the scientist who discovered electron.
Q 18.
What is the electronic configuration of a hydrogen atom
Q 19.
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 20.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 21.
What is mass number?
Q 22.
Fill in the blanks :
________ rays are negatively charged.
Q 23.
Fill in the blanks :
Anode rays are also called ___________.
Q 24.
Fill in the blanks :
_______ are atoms having the same mass number but different atomic numbers.
Q 25.
How does a proton differ from an electron ?
Q 26.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 27.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 28.
What name is given to those atoms which contain the same number of protons and electrons but different number of neutrons ?
Q 29.
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 30.
What were the observations of Rutherford's ?-scattering experiment?
Q 31.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 32.
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 | Symbol |
|---|
| 11 | 12 | ........ | ....... | ........ | ......... |
Q 33.
(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 34.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 35.
Name the shell of an atom which can accommodate a maximum of
(a) 2 electrons (b) 18 electrons
Q 36.
Which radioactive isotope is used to determine the activity of thyroid gland ?
Q 37.
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 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 are canal rays?
Q 40.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 41.
Name the radioactive isotope which is used in the treatment of cancer.
Q 42.
State one use of radioactive isotopes in industry.
Q 43.
What are cathode rays?
Q 44.
Who is known as 'Father of Nucleus Physics'?
Q 45.
What is ionization energy?
Q 46.
Fill in the blanks :
The _________ of an atom is dense, small in size and is positively charged.
Q 47.
Fill in the blanks :
Atomic number is equal to _____________.
Q 48.
Fill in the blanks :
The mass number of an atom is equal to the number of ________ in its nucleus.
Q 49.
Name the positively charged particle present in the atoms of all the element
Q 50.
What is the absolute mass and charge of an electron ?
