Question 1 :
The element with atomic number $14$ is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

Question 2 :
Refer to changes in properties of elements&#160;&#160;on moving left to right across a period of the periodic table.For each property , choose the letter corresponding to the correct answer from A,B,C and D.<br/>Atomic Size :

Question 3 :
Which of the following set of elements is written in order of theirincreasing metallic character?<br>

Question 5 :
Which of the following triads does not follow Dobereiner's law of triads?

Question 6 :
Out of $118$ elements known to us, how many elements occur naturally?

Question 8 :
Which of two elements among the following will display the most similar chemical properties?

Question 9 :
Which of the following is a correct statement about metallic atoms?

Question 10 :
Which among the following is not an anomalous pair in Mendeleev's periodic table?

Question 11 :
The family of elements having seven electrons in the valence shell is :

Question 12 :
If the two members of a Dobereiner triad are phosphorus and antimony, the third member of this triad is&#160;:<br/>

Question 15 :
Numbering of groups as 1, 2, ........... 18 was adopted by IUPAC in :

Question 20 :
Metals can produce sound when struck, this property of metals is known as sonority.

Question 21 :
A nuclide having one proton and one neutron is represented as$_{ 1 }^{ 1 }{ H }$.

Question 22 :
The atomic radii of the elements across the second period of ihe periodic table:

Question 24 :
An element $M$ has an atomic number 9 and atomic mass 19. Its negative ion will be represented by:

Question 25 :
Element X has twelve neutrons in its nucleus. To which group in the periodic table would it belong?

Question 28 :
Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? (Numbers in the brackets are atomic numbers)

Question 30 :
Assertion: Metallic character increases from left to right in a period. Reason: The higher the value of ionization energy, electronegativity and electron affinity the more is the metallic character of the element.

Question 31 :
Arrange the following elements in order of decreasing nonmetallic character: $Ge,\ Sn,\ Pb,\ Si$<br/>

Question 32 :
The third period contains elements. Out of these elements, how many elements are non-metals?&#160;<br/>

Question 33 :
Atomic radii of fluorine and neon in Angstorm units are respectively given by:

Question 35 :
All the $s-$ block elements of the periodic table are placed in the groups

Question 37 :
The period of element having three shells with three electrons in valence shell is:

Question 41 :
Assertion: The $ 5^{th} $ period of periodic table contains 18 elements not 32. Reason: n = 5 , $\ell$ = 0, 1, 2, 3. The order in which the energy of available orbitals 4d, 5s and 5p increases is 5s < 4d < 5p and the total number of orbitals available are 9 and thus 18 electrons can be accommodated.

Question 42 :
Among $P_{2}O_{5}, As_{2}O_{3}, Sb_{2}O_{3}$ and $Bi_{2}O_{3}$, the most acidic oxide is

Question 44 :
The correct order for decreasing atomic radius of the five atoms $H,\ Br,\ I,\ He$ and $S$ is :

Question 45 :
Which of the following statement(s) is/are true about the modern form of periodic table?<br/>

Question 47 :
Most transition metals from multiple cations, that is, they have more than one possible amount of positive charge. Virtually all of the transition metals form dipositive $(2+)$ cations, along with one or more other forms. For example, titanium forms $Ti^{2+}$ ad $Ti^{4+}$, and cobalt forms $Co^{2+}$ and $Co^{3+}$.<br>The principal exceptions to this predominance of cations with a $2^{+}$ charge are scandium and yttrium, which form only tripositive cations. $Sc^{3+}$ and $Y^{3+}$, and copper and silver, which form cations with a single positive charge. $Cu^{+}$ and $Ag^{+}$.<br>[While copper also forms dipositive $Cu^{2+}$, silver exhibits the single positive state essentially exclusively.]<br>Which of the following offers a POSSIBLE explanation for the existence of $Cu^{+}$ and $Ag^{+}$?

Question 48 :
Which of the following series correctly represents relations between the elements from X to Y?<br>$X \rightarrow Y$<br>

Question 49 :
Out of $Fe^{2+}, Fe^{3+}, Mn^{2+}$ and $Ti^{2+}$, the least size is of:

Question 50 :
An atom has electronic configuration $1{ s }^{ 2 }\ 2{ s }^{ 2 }2{ p }^{ 6 }\ 3{ s }^{ 2 }3{ p }^{ 6 }3{ d }^{ 3 }\ 4{ s }^{ 2 }$. It will be place it in :