1-Bohr’s theory is valid for any atom or ion having one electron.
Niels Henrik David Bohr
2-The sub states in a stationary state are called atomic orbitals.
3-Orbitals having same energy are called degenerate sub shells.
4-The shape of s orbital is spherical.
5-The shape of p orbital is dumb bell.
6-Rutherford proposed planetary model based on his alpha particles scattering experiment.
7-Quantum theory of radiation is proposed by Max Planck.
8-The number of sub-shells present in L-shell is 2.
9-The distance between the nucleus and outermost orbital gives the atomic radius.
10-The number of states present in the sub stationary stage of g is 9.
11-The number of states present in the sub stationary state ‘d’ is 5.
12-The ‘ l ‘(L) value for the O-Sub-shell is 2.
13-The units of atomic radius are Angstrom.
14-The unit of ionisation energy is electron volt.
15-Elements of atomic numbers from 57 to 71 are called Lanthanides.
16-Elements of atomic numbers between 89 to 103 are called Actenides.
17-All inert gases are placed in zero group in the periodic table.
Eight-column form of periodic table, updated with all elements discovered to 2014
18-The term transition elements in the periodic table applies to d block elements.
19-Addition of oxygen to a given compound is called Oxidation.
20-The first classification of elements is attempted by Dobereiner.
Johann Wolfgang Döbereiner
21-The modern periodic table has 7 periods.
22-The seventh period of periodic table is incomplete.
23-In a group the electronegativity decreases from top to bottom.
24-Addition of hydrogen to a given compound is called reduction.
25-According to modern periodic law the properties of elements are a periodic function of their electronic configuration.
26-According to Mendeleef the properties of elements are a periodic function of their atomic weights.
Dmitri Ivanovich Mendeleev
27-The ionisation energy reaches a maximumvalue for inert gases.
28-Electronegativity is represented on Pauling’s electronegativity scale.
29-The most electropositive element is Cesium.
30-The electronegativity of fluorine is 4.