Question:
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
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.
Describe briefly Thomson's model of an atom.
Q 4.
Write a short note on Nucleus.
Q 5.
Who discovered electrons?
Q 6.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 7.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 8.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 9.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 10.
How many times is a proton heavier than an electron ?
Q 11.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 12.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 13.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 14.
What is mass number?
Q 15.
Fill in the blanks :
Anode rays are also called ___________.
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.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 20.
What is ionization energy?
Q 21.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 22.
What is the absolute mass and charge of a proton ?
Q 23.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
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 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 26.
What is the absolute mass and charge of an electron ?
Q 27.
What is a proton ? How does it differ from a neutron ?
Q 28.
(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 29.
Name the scientist who discovered electron.
Q 30.
Name the shell of an atom which can accommodate a maximum of
(a) 2 electrons (b) 18 electrons
Q 31.
State one use of radioactive isotopes in medicine.
Q 32.
Fill in the blanks :
_______ are atoms having the same mass number but different atomic numbers.
Q 33.
Who discovered nucleus of an atom?
Q 34.
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 35.
What are canal rays?
Q 36.
What are cathode rays?
Q 37.
What were the observations of Rutherford's ?-scattering experiment?
Q 38.
Fill in the blanks :
________ rays are negatively charged.
Q 39.
How does a proton differ from an electron ?
Q 40.
What is a neutron ? State its relative mass and charge.
Q 41.
State the location of electrons, protons and neutrons in an atom.
Q 42.
What name is given to those isotopes which have unstable nuclei and emit various types of radiations ?
Q 43.
Complete the following table.
| Particle | Electron | Proton | Neutron |
|---|
| (i) Symbol | __ | __ | __ |
| (ii) Nature | __ | __ | __ |
| (iii) Relative Charge | __ | __ | __ |
| (iv) Absolute Charge | __ | __ | __ |
| (v) Relative Mass | __ | __ | __ |
| (vi) Absolute Mass | __ | __ | __ |
Q 44.
What are the limitations of Rutherford’s model of the atom?
Q 45.
Name the particles which actually determine the mass of an atom.
Q 46.
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 47.
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 48.
(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 49.
Name the fundamental particle not present in the nucleus of hydrogen atom
Q 50.
Who discovered X-Rays?
