Periodic Classification

A. Location of nucleus by Rutherford
B. Atomic number by Moseley
C. X-rays by Roentgen
D. Natural radioactivity by Henry Bacquerel.

A. Melting point of elements
B. Boiling point of elements
C. Ionization energy of elements
D. Coordination number of ions

A. Boron & Beryllium
B. Nitrogen & Phosphorous
C. Magnesium & Aluminium
D. Gallium & Helium

A. Same number of electrons in the valence shell
B. Similar physical state
C. Remarkable reducing properties
D. Homovalent (show same valency)

A. Acidic
B. Basic
C. Acidic and basic
D. Neutral and acidic

A. 2
B. 4
C. 8
D. 7

A. 2
B. 4
C. 6
D. 8

A. 6th
B. 7th
C. 2nd and 3rd both
D. 5th

A. less reactive
B. Zero group elements
C. Having completely filled valence shell
D. All

A. Hydrogen
B. Sodium
C. Copper
D. Germanium