attempts of classification

The scientist, who discovered that the nucleus of atom contains positively charged protons is .............

• Bohr

• Mendeleev

• Rutherford

• Moseley

The scientist who left vacancies in his table to be filled with suitable discovered elements in future is …….

• Mosely
• Rutherford
• Bohr
• Mendleev

Mendleev classified the elements of each group into ………sub-groups

• 2
• 3
• 4
• 5

The scientist ……….had discovered the main energy levels.

• Bohr
• Mendeleev
• Hofmann
• Mosely

The number of energy levels in the heaviest known atom is……levels

• 5
• 7
• 8
• 10

The number of elements which exists in nature is ………..

• 29
• 118
• 92
• 102

The number of elements in Mendeleev’s periodic table is …………. elements

• 92

• 118

• 67

• 76

Elements are arranged in Mendeleev's periodic table in an ascending order according to …..........

• atomic weight

• atomic number

• chemical activity

• valency

Elements in ................ periodic table are classified according to their atomic numbers in an ascending order and the way of filling of the energy sublevels with electrons.

• Moseley's

• Mendeleev's

• Rutherford's

• the modern

the horizontal row in mendeleev's table

• period

• group

• periodic table

• Moseley's periodic table