Test: Periodic Table - UPSC MCQ

The correct option is D.
In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the f-block columns (between groups 3 and 4) are not numbered.

The correct answer is A as Mendeleev classify 63 elements in his periodic table.

The lanthanides series include elements 58 to 71 which fill their 4f sublevel progressively. The actinides are elements 89 to 103 and fill their 5f sublevel progressively.The lanthanides are f-block elements which contain seven f-orbitals . The maximum electrons can be filled in f-orbitals are 14. Hence, lanthanides have a total 14 elements.The actinide series always includes the 14 elements with atomic numbers 90 through 103. The other members are (in order of increasing atomic number) thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium , californium, einsteinium , fermium, mendelevium, nobelium, and lawrencium.

At high temperature and high pressure Krypton and Xenon forms some compounds like Xenon, Tetrafluride, xenon Oxyfluride. 

Nitrogen is more electronegative than phosphorus. On moving down a group, the number of shell increases. Therefore, the valence electrons move away from the nucleus and the effective nuclear charge decreases. 

The correct option is B.
In first ionisation energy, we remove electron from a neutral atom but for second ionisation we have to remove electron from a positive atom, where electron are more tightly bounded due to increased attraction force so second ionisation energy is high relative to first IP.

The correct answer is A as t's configuration is 2,8,6 therefore it's valency is 2 as it needs two electrons to complete its octet.
It is a non metal because as we go from left to right in a periodic table the metallic character decreases while non-metallic character increases.

Fluorine is a halogen, which is group 17 on the periodic table, and the halogen are the most reactive.

The potassium atom has an extra electron shell compared to the sodium atom, which means it's valence electrons are further from the nucleus, giving potassium a larger atomic  radius. 

As atomic number increases along a period, ionization energy increases and in a group it decreases. For S and P, theoretically ionization energy of S should be greater than P but due to the stability of half filled electronic configuration, ionization energy of P is greater than S.

The correct option is D.

"Mg" will form dipostive ion becoz.... electronic configuration of Mg is 2,8,2..so to complete its octet it will lose 2 electrons...and form a dipositive ion.

Electron affinity of chlorine is more than fluorine. Carbon monoxide do not show basic and acidic properties when they react with water. Therefore, it is neutral oxide.

Energy is always released when a neutral atom gains an electron. This process is called electron affinity. It is reverse of ionization energy. Semimetals are also known as metalloids. Tellurium and polonium are one of the semi metals.

The correct option is B.
It is fairly easy to arrange the atoms according to atomic size. We know that atomic size increases from right to left and from top to bottom in the Periodic Table. The smallest atoms are at the top right and the largest atoms are at the lower left of the Periodic Table.Decreasing order of atomic size:
Li > Be > B > C > N > O > F
 

The correct option is D.
.. Even though it only has two electrons, it is grouped with elements that have eight valence electrons. Helium is still happy because its outermost shell is completely full making it extremely stable. The noble gases are happy with their completely filled valence shells.

In a Dobereiner's traid, the atomic mass of the middle element is roughly the average of the atomic mass of the other  2 elements. Thus,  
Atomic mass of Q = (at. mass of P+ at. mass of R) /2
⇒ 23 = 7+ m(R) /2 
⇒ 23*2 = 7+ m(R) 
⇒  46 -7 = m(R) 
⇒ atomic mass of R = 39 

The element gallium was discovered four year's after the publication of Mendeleev's table, and it's properties matched up remarkably well with ek aluminum, fitting into the table exactly where he had predicted. 

B is the correct option.The element with atomic number 3 has a EC of 2,1. Thus,it has a valency of  1. The element with atomic number 17 has the EC as 2,8,7. It will gain 1 electron to complete the octet. Thus, it has a valency of 1. The elements with atomic numbers 3 and 17 are li and cl respectively. The formula of the compound formed will be LiCl.