Q5 of 49 Page 147

An element X belongs to group 2 and period 3 of the periodic table. The chemical formulae of its nitrate, sulphate and phosphate respectively will be

The element X is magnesium. Its valency is 2 because it loses 2 electrons readily to combine with other reactants. Only d) option has the valency 2 for element X.

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3

An element X combines with hydrogen to form a compound XH3. The element Xis placed on the right side of the periodic table. Which of the following statement is correct for element X?

I. Has two valence electrons.


II. Is a metal and is solid.


III. Is a non-metal and is a gas.


IV. Has five valence electrons.


V. XH3 reacts with water to forma basic compound.

 4

Listed below are the locations of certain elements in groups and periods of the periodic table. Arrange these elements in the expected order of increasing non-metallic character:

I. Element in the fourth period and group IV A


II. Element in the third period and group VI A


III. Element in the fourth period and group VI A


IV. Element in the six period and group III A


V. Element in the second period and group VII A


The correct order is:

 6

An element belongs to group 17. It is present in third period and its atomic number is 17. What is the atomic number of the element belonging to same group and present in fifth period?

 7

Consider the following figure:


Here, p, q, r and s respectively are: