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.
Who discovered protons?
Q 3.
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 4.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 5.
Write a short note on Nucleus.
Q 6.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 7.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 8.
Describe briefly Thomson's model of an atom.
Q 9.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 10.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 11.
How many times is a proton heavier than an electron ?
Q 12.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 13.
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 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.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 18.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
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.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 21.
What is ionization energy?
Q 22.
Name the scientist who discovered electron.
Q 23.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 24.
What is a proton ? How does it differ from a neutron ?
Q 25.
State one use of radioactive isotopes in medicine.
Q 26.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 27.
Fill in the blanks :
_______ are atoms having the same mass number but different atomic numbers.
Q 28.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 29.
Fill in the blanks :
________ rays are negatively charged.
Q 30.
(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 31.
Which radioactive isotope is used to determine the activity of thyroid gland ?
Q 32.
Name the shell of an atom which can accommodate a maximum of
(a) 2 electrons (b) 18 electrons
Q 33.
What are cathode rays?
Q 34.
Fill in the blanks :
The mass number of an atom is equal to the number of ________ in its nucleus.
Q 35.
Fill in the blanks :
The maximum number of electrons that can be accommodated in K-shell are _______.
Q 36.
Which shell of an atom can accommodate a maximum of
(a) 8 electrons?
Q 37.
What is the absolute mass and charge of an electron ?
Q 38.
What is the absolute mass and charge of a proton ?
Q 39.
(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 40.
What are canal rays?
Q 41.
What were the observations of Rutherford's ?-scattering experiment?
Q 42.
What is Atomic Number? Who coined this term?
Q 43.
What is the electronic configuration of a hydrogen atom
Q 44.
What is the positive charge on the nucleus of an atom due to ?
Q 45.
State one use of radioactive isotopes in industry.
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 :
The total number of protons and neutrons in the nucleus of an atom is called its __________.
Q 48.
Fill in the blanks :
Atomic number is equal to _____________.
Q 49.
What is the maximum number of electrons which can be accommodated in the K shell of an atom
Q 50.
Name the particles which actually determine the mass of an atom.
