Question:
What valencies will be shown by the elements A, B, C, D and E having atomic numbers 2, 4, 8, 10, and 13 respectively.
Answer:
A = 0; B = 2; C = 2; D = 0; E = 3
Structure of the Atom
Q 1.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 2.
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 3.
Fill in the blanks :
Anode rays are also called ___________.
Q 4.
Who discovered protons?
Q 5.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 6.
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 7.
Describe briefly Thomson's model of an atom.
Q 8.
What is the absolute mass and charge of a proton ?
Q 9.
How many times is a proton heavier than an electron ?
Q 10.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 11.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 12.
What is mass number?
Q 13.
What is ionization energy?
Q 14.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 15.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 16.
If an atom contains one electron and one proton, will it carry any charge or not?
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.
Fill in the blanks :
Atoms are made up of __________, ___________ and __________.
Q 20.
Write a short note on Nucleus.
Q 21.
Fill in the blanks :
______ are atoms of the same element, which have same number of protons but different mass numbers.
Q 22.
Name the radioactive isotope which is used in the treatment of cancer.
Q 23.
Fill in the blanks :
Atomic number is equal to _____________.
Q 24.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 25.
What is the maximum number of electrons that can go into the N shell of an atom ?
Q 26.
State one use of radioactive isotopes in medicine.
Q 27.
What name is given to those isotopes which have unstable nuclei and emit various types of radiations ?
Q 28.
Fill in the blanks :
The fundamental particle not present in hydrogen atom is __________.
Q 29.
Fill in the blanks :
Nucleons are __________ and ___________.
Q 30.
Which shell of an atom can accommodate a maximum of
(a) 8 electrons?
Q 31.
How does an electron differ from a neutron ?
Q 32.
(a) Describe Bohr's model of the atom. How did Neils Bohr explain the stability of atom ?
(b) An element has an atomic number of 11 and its mass number is 23. What is the arrangement of electrons in the shells ? State nuclear composition of an atom of the element.
Q 33.
State one use of radioactive isotopes in industry.
Q 34.
Fill in the blanks :
________ rays are negatively charged.
Q 35.
Fill in the blanks :
The _________ of an atom is dense, small in size and is positively charged.
Q 36.
Fill in the blanks :
The mass number of an atom is equal to the number of ________ in its nucleus.
Q 37.
What is the maximum number of electrons which can be accommodated in the K shell of an atom
Q 38.
Name the particles which actually determine the mass of an atom.
Q 39.
What do you understand by the term 'electronic configuration' of an element ? Write down the electron configuration of oxygen (At. No. = 8).
Q 40.
What is a proton ? How does it differ from a neutron ?
Q 41.
State whether the following statement is true or false :
Radioactive isotope of iodine is used for making the medicine called tincture iodine.
Q 42.
What name is given to those atoms which contain the same number of protons and electrons but different number of neutrons ?
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 | Valency |
|---|
| 11 | 12 | ........ | ....... | ........ | ......... |
Q 44.
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 45.
(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 46.
Name the fundamental particle not present in the nucleus of hydrogen atom
Q 47.
Who discovered neutrons?
Q 48.
What were the observations of Rutherford's ?-scattering experiment?
Q 49.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 50.
Describe Bohr’s model of the atom.
