Small Important Questions

Question 1

Name the sub — atomic particles of an atom.

Answer 1

Proton
Neutron
Electron

Question 2

Name the scientist who formulated the atomic structure

Answer 2

John Dalton

Question 3

What is the e/m ratio of an electron

Answer 3

according to Thomson’s experiment 1.76x10^3, every gram of electron carries the following charge

Question 4

name of the scientist who first gave the atomic model

Answer 4

JJ Thomson

Question 5

what is an isotope

Answer 5

atoms with the same atomic number but different mass number are called isotopes, they have similar chemical properties

Question 6

what are isobars

Answer 6

atoms with the same mass number but different atomic numbers are called isobard they have different chemical properties but same physical properties

Question 7

define photoelectric effect

Answer 7

when the surface of alkali metals like potassium and calcium emit electrons when a beam of light with high frequency is projected on them is called photoelectric effect

Question 8

What is an atomic number?

Answer 8

Atomic number is the measure of the number of protons which is present in
the nucleus of an atom.

Question 9

What is a mass number?

Answer 9

Mass number of an element is the sum of the number of protons and
neutrons present in the nucleus of an atom

Question 10

How does the intensity of light affect photoelectrons?

Answer 10

The number of electrons ejected and kinetic energy associated with them is
directly proportional to the intensity of light projected towards the metal.

Question 11

Quantum Numbers

Answer 11

Quantum numbers are 4 different QN which together lets us know the probable location of an electron in orbit.

Question 12

Principle quantum number

Answer 12

this quantum number lets us know the size of the atom; it is denoted by “N” where n is the shell in which the electron is present. Bigger the number further away the electron is

Question 13

Azimuthal Quantum Number

Answer 13

It represents the subshell in which electrons belong to, it also gives us the shape of the orbitals. Azimuthal quantum number is denoted by the letter “l” in which l = (n-1).

Question 14

Magnetic Quantum Number

Answer 14

This QN gives us all the possible orbitals/orientations possible for a specific in a subshell. It is represented my ML and ML = -L 0 +L

Question 15

Spin Quantum Number

Answer 15

This gives us the information of spin direction of the electron. These possible values are +1/2 and -1/2

Question 16

Bond Order

Answer 16

Its defined as half of the difference between the no of electrons present in the bonding electrons and anti-bonding electrons (BO = ½ (ES1 – ES2))

Question 17

Hund’s rule of maximum multiplicity

Answer 17

All the pairing of electrons will only take place if all the orbitals are occupied with a single electron

Question 18

Paulis exclusion principle

Answer 18

No 2 elements can have the same value for all 3 quantum numbers

Question 19

Aufbau principle of maximum multiplicity

Answer 19

The elements are arranged in the orbitals in the increasing order of their energy

Question 20

Molecular orbital theory

Answer 20

each atom tends to combine together and form molecular orbitals.

Question 21

Valence bond theory

Answer 21

Those atoms which have opposite spin electrons overlap with each other to form a bond between the 2 atoms, as this overlapping increases the stability of the bond also increases

Question 22

Polarity of bonds

Answer 22

the existence of positive and negative charged electrons are called polarity of bonds

Question 23

Dipole Movement

Answer 23

dipole movement is defined as the measure of polarity of a bond

Question 24

Bohr’s Atom model

Answer 24

the model which can represent each shell in which the electrons are present are called bohr’s atomic model

Question 25

Heisenberg Uncertainty principle

Answer 25

It states that it is impossible to determine the velocity and position of an microparticle simultaneously

Question 26

Demerits Bohr’s model

Answer 26

• Couldn’t explain the dine details of hydrogen spectrum
• Couldn’t explain the spectrum of atom other than hydrogen
• Couldn’t explain the formation of molecules by chemical bonding
• Couldn’t explain Zeeman and stark effect

Question 27

iso electron species

Answer 27

the species (different elements) with the same number of electrons is called iso electron species