Periodic classification of elements

Upto which element, the Law of Octaves was found applicable?

• CALCIUM

• MAGNESIUM

• ALUMINIUM

• POTASSIUM

Select the correct arrangement of following elements in doberieners triads Sr, K, Ca, Br, Na, Ba, Cl, I, Li

• i) Li Sr K ii) Ca Na Ba iii) Cl Br I

• i) Li Na K ii) Ca Sr I iii) Cl Br Ba

• i) Li Na K ii) Ca Sr Ba iii) Cl Br I

• i) Ca Na K ii) Li Sr Ba iii) Cl Br I

At the time of Mendeleev, the number of elements known was

• 62

• 61

• 63

• 56

An atom of an element has the electronic confi-guration 2,8,2. To which group does it belong?

• 4th group

• 2nd group

• 3rd group

• 6th group

Which of the following belong to same period?

Element A B C D E

Atomic No 3 2 14 9 6

• DEA

• BCD

• ABC

• ADE

Pick out the chemically most reactive elements from the given set of elements

Li, Na, K F, Cl, Br

• Li and F

• Li and Br

• Na and Cl

• K and F

Which one of the following statements is not correct about the trends in the properties of the elements of a period on going from left to right?

• oxides become more acidic

• the atom gains electrons readily

• the element becomes more metallic

• there is increase in no of valence electrons

A metal ‘M’ is in the first group of the Periodic Table. What will be the formula of its oxide?

• MO

• M2O

• MO2

• M2O3

An element X has mass number 40 and contains 21 neutrons in its atom. To which group of the Periodic Table does it belong?

• Group 1

• Group 3

• Group 2

• Group 4

An element ‘A’ belongs to the third period and group 16 of the Periodic Table. Find out the valency of A.

• Valency = 1

• Valency = 2

• Valency = 3

• Valency = 6