Element X forms a chloride with the formula XCl₂ , which is a solid a high melting point. X would most likely be in the same group of the Periodic Table as :

Which of the following statements about the Modern Periodic Table is correct:

Which of the following is the outermost shell for elements of period 2? 

Which one of the following elements exhibit maximum number of valence electrons?

Arrange the following elements in the order of their decreasing metallic character: Na, Si, Cl, Mg, Al

Arrange the following elements in the order of their increasing nonmetallic character : Li, O, C, Be, F

What type of oxide would Eka-aluminium form?

Which of the following elements will form an acidic oxide?

Which one of the following does not increase while moving down the group of the periodic table?

On moving from left to right in a period in the periodic table, the size of the atom.

What were the criteria used by Mendeleev in creating his Periodic Table?

Why do you think noble gases are placed in a separate group?

In the Modern Periodic Table, which are the metals among the first ten elements?

By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?
Ga, Ge, As, Se, Be

(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?

Predict the group of an element A if its atomic number is 16.

Write the formulae of chloride of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.

Three elements X, Y and Z have 3,4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.

Arrange the following elements in the increasing order of their metallic character Mg, Ca, K, Ge, Ga

Identify the elements with the following property and arrange them in increasing order of their reactivity
(a) An element which is a soft and reactive metal
(b) The metal which is an important constituent of limestone
(c) The metal which exists in liquid state at room temperature

Mendeleev' predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.
(a) Name the elements which have taken the place of these elements.
(b) Mention the group and the period of these elements in the Modern Periodic Table.
(c) Classify these elements as metals, non-metals or metalloid.
(d) How many valence electrons are present in each one of them?

An element A which is a yellow solid at room temperature shows catenation and allotropy. A forms two oxides which are also formed during the thermal decomposition of ferrous sulphate crystals and are the major air pollutants.
(a) Identify the element A
(b) Write the electronic configuration of A
(c) Write the balanced chemical equation for the thermal decomposition of ferrous sulphate crystals?
(d) What would be the nature (acidic/ basic ) of oxides formed?
(e) Locate the Position of the element in the Modern Periodic Table.

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason

Give an account of the process adopted by Mendeleev for the classification of elements. How did he arrive at "Periodic Law"?