Multiple Choice Questions 10×1=10
1
How many electrons can be accommodated at the most in the third shell of the elements?
2
What information was obtained from discharge tube experiments?
A
Structure of atom was discovered
B
Neutrons and protons were discovered
C
Electrons and protons were discovered
D
Presence of nucleus in an atom was discovered
3
What does keep the particles present in the nucleus intact?
A
Particles are held together by strong nuclear force
B
Particles are held together by weak nuclear force
C
Particles are held together by electrostatic force
D
Particles are held together by dipolar force
4
Which particle has no charge?
A
Proton
B
Neutron
C
Electron
D
All of these
5
Number of ……… is always fixed in atom of an element.
A
Proton
B
Neutron
C
Electron
D
None of these
6
Atomic mass is represented by:
7
Atomic mass of sodium is:
8
Number of neutrons in C-12 is:
9
The relative atomic masses of elements are expressed in:
A
Gram
B
Kilogram
C
amu
D
Joule
10
Relative Atomic mass of krypton is:
A
83.7
B
80.9
C
82.04
D
None of these
Short Answer Questions 15×2=30
i
Why is it needed to lower the pressure of the gas inside the discharge tube? Constructed Response
ii
A system just like our solar system exists in an atom. Comment on this statement. Investigative
iii
How many neutrons are present in ________? (Fill in the blank with appropriate element)
iv
How many times cesium bigger than helium?
v
Differentiate between shell and sub shell with examples of each.
vi
What are sub-atomic particles?
vii
How almost all the mass of atom is concentrated in the nucleus? (directed toward nucleus)
viii
How can we see an atom?
xi
How ions and isotopes are formed?
xii
What is the atomic number of carbon?
xiii
Can two elements have the same atomic mass but different atomic number?
xiv
What is Relative atomic mass?
xv
Calculate the number of neutrons, protons and electrons in barium \( \frac{137}{56} \) Ba
Example 1: Barium atom notation: \( \frac{137}{56} \) Ba
Atomic mass (A) = 137, Atomic number (Z) = 56
Number of protons = Z = 56
Number of electrons = Number of protons = 56 (in neutral atom)
Number of neutrons = A – Z = 137 – 56 = 81