Question:
Fill in the blanks :
Valency is the __________ _____________ of an atom.
Answer:
combining capacity
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.
Describe briefly Thomson's model of an atom.
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.
Who discovered protons?
Q 5.
Write a short note on Nucleus.
Q 6.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 7.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 8.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 9.
Who discovered electrons?
Q 10.
What is mass number?
Q 11.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 12.
Fill in the blanks :
Anode rays are also called ___________.
Q 13.
How many times is a proton heavier than an electron ?
Q 14.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 15.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 16.
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 17.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 18.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 19.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 20.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 21.
What is ionization energy?
Q 22.
What is the absolute mass and charge of a proton ?
Q 23.
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 24.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 25.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 26.
What is a proton ? How does it differ from a neutron ?
Q 27.
Name the scientist who discovered electron.
Q 28.
What is the absolute mass and charge of an electron ?
Q 29.
State one use of radioactive isotopes in medicine.
Q 30.
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 31.
Who discovered nucleus of an atom?
Q 32.
Which shell of an atom can accommodate a maximum of
(a) 8 electrons?
Q 33.
Name the shell of an atom which can accommodate a maximum of
(a) 2 electrons (b) 18 electrons
Q 34.
(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 35.
What name is given to those atoms which contain the same number of protons and electrons but different number of neutrons ?
Q 36.
What are the properties of anode rays?
Q 37.
What is the mass of proton as compared to electron?
Q 38.
What are ?-particles?
Q 39.
What were the observations of Rutherford's ?-scattering experiment?
Q 40.
Fill in the blanks :
The mass number of an atom is equal to the number of ________ in its nucleus.
Q 41.
Fill in the blanks :
_______ are atoms having the same mass number but different atomic numbers.
Q 42.
Name the positively charged particle present in the atoms of all the element
Q 43.
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 44.
Give one example of a radioactive isotope which is used as a fuel in the reactors of nuclear power plants.
Q 45.
Name the radioactive isotope which is used in the treatment of cancer.
Q 46.
What name is given to the pair of atoms such as
N and
N ?
Q 47.
What name is given to those isotopes which have unstable nuclei and emit various types of radiations ?
Q 48.
Who discovered neutrons?
Q 49.
What are cathode rays?
Q 50.
Complete the following table.
| Particle | Electron | Proton | Neutron |
|---|
| (i) Symbol | __ | __ | __ |
| (ii) Nature | __ | __ | __ |
| (iii) Relative Charge | __ | __ | __ |
| (iv) Absolute Charge | __ | __ | __ |
| (v) Relative Mass | __ | __ | __ |
| (vi) Absolute Mass | __ | __ | __ |
