Small Important Questions Flashcards
Name the sub — atomic particles of an atom.
Proton
Neutron
Electron
Name the scientist who formulated the atomic structure
John Dalton
What is the e/m ratio of an electron
according to Thomson’s experiment 1.76x10^3, every gram of electron carries the following charge
name of the scientist who first gave the atomic model
JJ Thomson
what is an isotope
atoms with the same atomic number but different mass number are called isotopes, they have similar chemical properties
what are isobars
atoms with the same mass number but different atomic numbers are called isobard they have different chemical properties but same physical properties
define photoelectric effect
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
What is an atomic number?
Atomic number is the measure of the number of protons which is present in
the nucleus of an atom.
What is a mass number?
Mass number of an element is the sum of the number of protons and
neutrons present in the nucleus of an atom
How does the intensity of light affect photoelectrons?
The number of electrons ejected and kinetic energy associated with them is
directly proportional to the intensity of light projected towards the metal.
Quantum Numbers
Quantum numbers are 4 different QN which together lets us know the probable location of an electron in orbit.
Principle quantum number
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
Azimuthal Quantum Number
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).
Magnetic Quantum Number
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
Spin Quantum Number
This gives us the information of spin direction of the electron. These possible values are +1/2 and -1/2
Bond Order
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))
Hund’s rule of maximum multiplicity
All the pairing of electrons will only take place if all the orbitals are occupied with a single electron
Paulis exclusion principle
No 2 elements can have the same value for all 3 quantum numbers
Aufbau principle of maximum multiplicity
The elements are arranged in the orbitals in the increasing order of their energy
Molecular orbital theory
each atom tends to combine together and form molecular orbitals.
Valence bond theory
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
Polarity of bonds
the existence of positive and negative charged electrons are called polarity of bonds
Dipole Movement
dipole movement is defined as the measure of polarity of a bond
Bohr’s Atom model
the model which can represent each shell in which the electrons are present are called bohr’s atomic model
