4.structure of atom Flashcards
Which aspect of Dalton’s atomic theory was proven incorrect by the discovery of electrons and protons?
Atoms are indivisible and indestructible
Who was the first scientist to propose a model for the structure of an atom?
J.J. Thomson
According to J.J. Thomson’s model, what analogy did he use to describe the atom’s structure?
(B) Christmas pudding
(C) Watermelon seeds
Question: What are alpha (α) particles?
Doubly-charged helium ions
According to Thomson’s atomic model, what is the relationship between positive and negative charges in an atom?
Both charges are equal in magnitude
What was the primary objective of Rutherford’s gold foil experiment?
To understand how electrons are arranged within an atom
Rutherford concluded that the positive charge in an atom is
Concentrated in a small region called the nucleus
Rutherford’s nuclear model of the atom proposed that
Electrons revolve around the nucleus in circular paths
Question: What was a major drawback of Rutherford’s atomic model?
It could not explain the stability of the atom
Question: According to Bohr’s model, what happens to electrons when they revolve in discrete orbits?
(A) They radiate energy continuously
(B) They do not radiate energy
(C) They lose mass
(D) They merge with the nucleus
They do not radiate energy
Which scientist proposed the concept of discrete orbits in the atom?
Neils Bohr
Rutherford is known as the “Father” of which field
Nuclear Physics
The energy levels in an atom are represented by which letters according to Bohr’s model?
K, L, M, N
Who discovered the neutron
J. Chadwick
Neutrons are present in the nucleus of all atoms except:
(A) Helium
(B) Carbon
(C) Hydrogen
(D) Oxygen
(C) Hydrogen
The mass of an atom is primarily determined by the sum of the masses of
Protons and neutrons
Question: Who proposed the rules for the distribution of electrons into different orbits of an atom?
(A) J.J. Thomson and Rutherford
(B) Bohr and Bury
(C) Dalton and Chadwick
(D) Einstein and Planck
(B) Bohr and Bury
What formula is used to calculate the maximum number of electrons in a shell?
(A) 2n
(B) 2n²
(C) n²
(D) n/2
B) 2n²
What is the maximum number of electrons that the K-shell can hold?
2
How many electrons can the L-shell accommodate according to Bohr’s model?
8
What is the maximum number of electrons that the M-shell can hold?
18
According to the rules of electron distribution, what is the maximum number of electrons that can be accommodated in the outermost orbit?
8
Question: According to Bohr’s distribution rule, electrons are not accommodated in a shell unless:
(A) The outermost shell is filled first
(B) The inner shells are filled
(C) There are no protons
(D) The atom is unstable
(B) The inner shells are filled
What is the maximum number of electrons the N-shell can hold according to the 2n² rule?
(A) 8
(B) 18
(C) 24
(D) 32
(D) 32
Q: What are the electrons present in the outermost shell of an atom called?.
Valence electrons
Q: What is the term used to describe an outermost shell with eight electrons?
A) Duplet
B) Octet
C) Sextet
D) Decet
B) Octet
According to the Bohr-Bury scheme, what is the maximum number of electrons that can be accommodated in the outermost shell of an atom?
Q: What is the valency of magnesium, which has two electrons in its outermost shell?
A) One
B) Two
C) Three
D) Four
two
Q: What is the primary reason why atoms react with other atoms to form molecules?
A) To increase their energy
B) To achieve an octet in the outermost shell
C) To decrease their mass number
D) To lose protons
B) To achieve an octet in the outermost shell
: What is the valency of oxygen if its outermost shell contains 6 electrons?
A) 2
B) 4
C) 6
D) 8
2
Which of the following elements has a valency of zero?
A) Chlorine
B) Argon
C) Sodium
D) Magnesium
argon
What does the atomic number (Z) of an element represent?
protone
: What determines the identity of an element?
A) The number of electrons in its outer shell
B) The number of neutrons in the nucleus
C) The number of protons in the nucleus
D) The overall charge of the atom
C) The number of protons in the nucleus
Q: The atoms of which element have isotopes protium, deuterium, and tritium?
hydrogen
Isotopes are defined as atoms of the same element that have:
A) Different numbers of protons
B) Different mass numbers
C) Different numbers of electrons
D) Different chemical properties
B) Different mass numbers
Q: An isotope of which element is used in the treatment of cancer?
A) Uranium
B) Iodine
C) Cobalt
D) Calcium
) Cobalt
Q: An isotope of iodine is specifically used for the treatment of which condition?
A) Cancer
B) Goitre
C) Diabetes
D) Tuberculosis
B) Goitre
Which of the following subatomic particles has the least mass?
(a) Proton
(b) Neutron
(c) Electron
(d) Alpha particle
(c) Electron
