Atomic structure

11.Who discovered the wave nature of electron?
 
A. Thomson
 
B. Louis de Broglie
 
C. Rutherford
 
D. Heisenberg
 
Option “D” is correct.
Louis-Victor de Broglie discovered the wave nature of electrons. He was awarded the Nobel Prize in Physics for this discovery.
12.What is the smallest particle of an element called?
 
A. atom
 
B. electron
 
C. neutron
 
D. Proton
 
Option”A” is correct.
13.According to Dalton’s atomic theory, the smallest particle in which matter can exist is called:
 
A. molecule
 
B. neutron
 
C. proton
 
D. ion
 
Option”B” is correct.

1. Matter is made up of very small undivisible particle called atoms.

2. All the atoms of a given element is identical in all respect i.e. mass, shape, size, etc.

3. Atoms cannot be created nor destroyed by any chemical process.

4. Atoms of different elements are different in nature.

14.Chemical behavior of an atom is determined by__
 
A. Atomic number
 
B. Mass number
 
C. Binding energy
 
D. Number of isotopes
 
Option “C” is correct.
Chemical behaviour of an atom is determined by its atomic number.
15.The mass number of an atom is the sum of number of:
 
A. protons and electrons
 
B. protons and nucleons
 
C. protons and neutrons
 
D. electrons and nucleons
 
Option “C” is correct.

The sum of number of protons and neutrons in the nucleus of an atom of an element is called its mass number. Mass number is denoted by A.
Mass number (A) = number of protons + number of electrons

16.The number of ______ is equal to the difference between the mass number of the atom and the atomic number.
 
A. Both protons and electrons
 
B. Neutrons
 
C. Electrons
 
D. Protons
 
Option “B” is correct.
The atom is composed of the proton, the neutron, and the electron.
Protons and neutrons make up the nucleus of the atom, whereas the negatively charged electrons revolve around the nucleus.
The number of protons found in the nucleus equals the number of electrons that surround it
Protons and neutrons have nearly equal masses, but they differ in charge.
Protons:
The number of protons within the nucleus of a given atom is equal to the atomic number of the corresponding element.
For example, the atomic number of helium is two. Therefore, the number of protons is also two.
Neutrons:
The number of neutrons within the nucleus of a given atom can be found by subtracting the atomic number from the atomic mass i.e difference between the mass number of the atom and the atomic number.
The mass number is equal to the sum of protons and neutrons in an atom.
Example Sodium, Na has Atomic Number is 11 and the Mass number is 23.
So Protons are 11, Neutrons are 12, and electrons are 11.
17.The nuclear particle having no mass and no charge, but only spin is
 
A. Electron
 
B. Proton
 
C. Neutrino
 
D. Meson
 
Option “C” is correct.
A neutrino is a fermion (an elementary nuclear particle with half-integer spin). It is electrically neutral and has negligible mass.
18.The total energy of an electron in an atom in an orbit is -3.4 eV. Its kinetic energy and potential energies are respectively:
 
A. -3.4 eV, -3.4 eV
 
B. -3.4 eV, -6.8 eV
 
C. 3.4 eV, -6.8 eV
 
D. 3.4 eV, 3.4 eV
 
Option “C” is correct.
19.Rutherford’s scattering experiment is related to the size of the:
 
A. nucleus
 
B. atom
 
C. electron
 
D. neutron
 
Option “A” is correct.
Rutherford scattering experiment is related to size of the nucleus. Rutherford defined that an atom consists of a large space where α− particles pass through, but only at a small region they are deflected. This region is nucleus.
20.______ discovered that the nucleus is positively charged
 
A. Thomson
 
B. Rutherford
 
C. Bohr
 
D. James Chadwick
 
Option “B” is correct.