Classification of Elements and Periodicity in Properties

Newlands could classify elements only upto

• Copper.

• Chlorine.

• Calcium.

• Chromium.

The most significant contribution towards the development of periodic table was made by

• Mendeleev.

• Avogadro.

• Dalton.

• Cavendish.

The number of elements known at present is ___.

• 31

• 114

• 63

• 75

Law of Triads was referred to as ___ relationship.

• Lothar Meyer's

• Mendeleev's

• Newlands's

• Dobereiner's

Which of the following statements is incorrect for periodic classification of elements?

• The properties of elements are periodic function of their atomic numbers.

• Non-metallic elements are less in number than metallic elements.

• For transition elements,the 3d-orbital are filled with electrons after 3p-orbitals and before 4s-orbitals

• The first ionisation enthalpies of elements generally increase with increase in atomic number as we go long a period.

Which of the following sets has strongest tendency to form anions?

• Ga, In, Tl

• Na, Mg, Al

• N, O, F

• V, Cr, Mn

French geologist A.E.B.de Chancourtois arranged the then known elements in order of ___ and made a ___ table of elements to display the periodic recurrence of properties.

• increasing atomic weights; cylindrical

• increasing atomic weights; rectangular

• decreasing atomic weights; cylindrical

• decreasing atomic weights; rectangular

According to the periodic Law of elements, the variation in properties of elements is related to their

• nuclear masses.

• atomic number.

• nuclear neutron-proton number ratios.

• atomic masses.

Mendeleev classified elements in

• increasing order of atomic groups.

• eight periods and eight groups.

• six periods and eight groups.

• eight periods and seven groups

Noble gases were included in Mendeleev's periodic table in the

• 1st Group.

• 7th Group.

• 8th Group.

• None of these