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All questions of Periodic Table for Year 10 Exam

In the Modern Periodic Table, if an element with atomic number ‘X’ is an inert gas, then an element with atomic number (X-1) will be placed in:​
  • a)
    Group 16
  • b)
    Group 17
  • c)
    Group 15
  • d)
    Group 18
Correct answer is option 'B'. Can you explain this answer?

Arun Sharma answered
All the Noble gases are placed in the group 18 and all elements are placed in the order of increasing atomic number. Therefore, the elements of atomic number before the Noble gas is placed in the before group of the period of Nobel gas which is group 17.
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Which of the following elements would lose an electron easily ?
  • a)
    Mg
  • b)
    Na
  • c)
    K
  • d)
    Ca
Correct answer is option 'C'. Can you explain this answer?

Pooja Shah answered
As we move down a group in the periodic table, the tendency to lose electron increases.
Also when we move from left to right in a period, the tendency to lose electrons decreases. Combining these two results, K will lose the electron most easily.

The Law of Octaves was applicable only upto element ________.
  • a)
    Sodium
  • b)
    Calcium
  • c)
    Zinc
  • d)
    Copper
Correct answer is option 'B'. Can you explain this answer?

Vikram Kapoor answered
The major limitations of Newlands' law of octaves were : 
It was applicable to only lighter elements having atomic masses upto 40 u, i.e., upto calcium. After calcium, the first and the eighth element did not have similar properties. For example chromium (Cr) and yttrium (Y) are the first and the eighth element placed in the same column but they have entirely different properties.  

Upto which element, the Law of Octaves was found to be applicable ?
  • a)
    Oxygen
  • b)
    Calcium
  • c)
    Cobalt
  • d)
    Potassium
Correct answer is option 'B'. Can you explain this answer?

Amit Kumar answered
The Law of Octave was found to be applicable upto calcium as after that every eighth element did not possess properties of the first element.

P, Q, R are elements of Dobereiner’s triads. If the atomic mass of P is 7 and that of Q is 23, What will be the atomic mass of R?
  • a)
    15.0
  • b)
    40.0
  • c)
    30.0
  • d)
    39.0
Correct answer is option 'D'. Can you explain this answer?

Gaurav Kumar answered
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 elements of group 16 are called
  • a)
    Chalcogens
  • b)
    Halogens
  • c)
    Pnicogens
  • d)
    Noble gases
Correct answer is option 'A'. Can you explain this answer?

Vikram Kapoor answered
The group 16 elements of modern periodic table consist of 5 elements oxygen, sulphur, selenium, tellurium and polonium. The elements in this group are also known as the chalcogens. 

How many triads could Dobereiner identify from the elements known at that time?
a) 3
b) 5
c) 4
d) 2
Correct answer is option 'A'. Can you explain this answer?

Pooja Shah answered
In 1817 a German chemist Johann Wolfgang Döbereiner arranged the elements with similar properties into groups.
Some groups were identified having three elements each. So he called these groups ‘triads’. Only three triads could be identified from the elements discovered at that time.

How many elements are placed in lanthanide and actinide series?
  • a)
    57, 89
  • b)
    14, 14
  • c)
    89, 57
  • d)
    14, 16
Correct answer is option 'B'. Can you explain this answer?

Neha Patel answered
14 elements
The same holds for the actinide series that runs from atomic number 90 through to number 103, again 14 elements. Thus, as you move from thorium (Th) at element number 90, you begin to fill up the 5f sublevel and continue to fill up the 5f sublevel until you finish the actinide series at lawrencium (Lr).

Which of the following triads is a Dobereiner’s Triad?
  • a)
    N, P, As
  • b)
    S, O, H
  • c)
    Na, Ra, Al
  • d)
    Li, Na, K
Correct answer is option 'D'. Can you explain this answer?

Anjana Khatri answered
DOBEREINER TRIADS RULE :
In 1817, Johann walfgang dobereiner. A German chemist, arranged the elements is group of three elements and in a manner that the atomic mass of middle element was roughly the average of the atomic masses of the other two elements of the triad.
Example:
In the triad of lithium, sodium and potassium. The atomic mass of lithium is 7 and  the atomic mass of potassium is 39. The average of masses of lithium and potassium gives atomic mass of sodium 23. 

Which of the following has the maximum non-metallic character ?
  • a)
    F
  • b)
    Cl
  • c)
    Br
  • d)
    I
Correct answer is option 'A'. Can you explain this answer?

Ananya Das answered
Non metallic character decreases as we move down the group. In a group, the size of an element increases because there is an addition of new shell and electron  is added in that shell. Hence, fluorine has the most non metallic character. 

The most distinctive property of the noble gases is that they are:
  • a)
    Unreactive
  • b)
    Radioactive
  • c)
    Metalloid
  • d)
    Metallic
Correct answer is option 'A'. Can you explain this answer?

Because, their valency is zero.
ie., their outer shell (orbital) of electrons is "full", significantly limiting their ability to form chemical bonds. (A chemical bond is essentially a region lying between two atoms with a maximum probability for electrons to be present. The electrons in the 'bond' are kinda shared between both the atoms, and they keep the repelling nuclei of the two atoms together by being electrostatic-ally attracted to both. In quantum chemistry (using Schroedinger's equation), it is seen that, the state with the 'orbitals' being filled have a 'lower free energy' than states with unfilled orbitals. Atoms without filled orbitals react so as to achieve this 'lower energy' stable state. This is explained by the valence-bond theory/molecular orbital theory models).

All the noble gases have all their orbitals full, and hence their 'unfilled states in the orbitals available for bonding' (valency) is zero. This significantly reduces their ability to bond with other atoms. This is why, noble gases are very unreactive.

Which of the following is correct order of atomic size 
  • a)
    Cl < F < Br < I
  • b)
    F < Cl < Br < I
  • c)
    I < Br < Cl < F
  • d)
    Br < I < Cl < F 
Correct answer is option 'B'. Can you explain this answer?

Amit Kumar answered
Trend of atomic size is :- 
In period it decreases due to large Electronegativity . In group it increases due to low  Electronegativity. According to this order, option ( b) is correct. 

Which of the following gives the correct increasing order of the atomic radii of O, F and N ?
  • a)
    O, F, N
  • b)
    N, F, O
  • c)
    O, N, F
  • d)
    F, O, N
Correct answer is option 'D'. Can you explain this answer?

Amit Sharma answered
Moving from right to left the periodic table metallic character increases and if metallic character increase atomic size will also increase as a result atomic radii increase.

Lanthanides belong to which period?
  • a)
    4
  • b)
    5
  • c)
    6
  • d)
    7
Correct answer is option 'C'. Can you explain this answer?

Vikram Kapoor answered
Lanthanides belong to 6th period.They start from atomic number 58 and ends in 71

Which one of the following elements exhibit maximum number of valence electrons ?
  • a)
    Na
  • b)
    Al
  • c)
    Si
  • d)
    P
Correct answer is option 'D'. Can you explain this answer?

Pooja Shah answered
The greater the valency of the element, the greater is its unreactivity. Also, the valency in a period increases from the left to the middle, then again decreases from middle to the right. So we can say that the unreactive elements are located in the center of the period. Since phosphorus and Silicon are located at the center, they have the highest number of Valence electrons, and hence are the most unreactive in the period.

Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period ?
  • a)
    A, B, C
  • b)
    B, C, D
  • c)
    A, D, E
  • d)
    B, D, E
Correct answer is option 'B'. Can you explain this answer?

Amit Kumar answered
At no. of elements a,b,c,d,e are 2,3,7,10,30Elements b , c , d belongs to the same period because the no. of valence shells are all 2. Elements B (Li), C (N) and D (Ne) belong to the same group.

Electropositive character of elements in a period ___________ from left to right
  • a)
    remains the same
  • b)
    Increases
  • c)
    decreases
  • d)
    All of these
Correct answer is option 'C'. Can you explain this answer?

Rahul Kapoor answered
Electropositive character in a period from left to right
Metallic character decreases across a period from left to right. On the other hand non-metallic character increases with increase in atomic number across a period.

In the third period of the periodic table the element having smallest size is        
  • a)
    Na        
  • b)
    Ar
  • c)
    Cl
  • d)
    Si
Correct answer is option 'C'. Can you explain this answer?

Pooja Shah answered
The correct answer is option 3: Cl (chlorine). Among the elements listed, chlorine (Cl) has the smallest size in the third period of the periodic table. Sodium (Na) and silicon (Si) are in the third period as well but have larger atomic sizes. Argon (Ar) is a noble gas and is not in the same period as the other elements mentioned.

Which of the following elements of noble gases participate in chemical reaction?
  • a)
    Kr, Rn
  • b)
    He, Kr
  • c)
    Rn, He
  • d)
    He, Ne
Correct answer is option 'A'. Can you explain this answer?

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

Which of the following has largest atomic size ?
  • a)
    Be
  • b)
    C
  • c)
    O
  • d)
    F
Correct answer is option 'A'. Can you explain this answer?

Neha Patel answered
Has the largest atomic number just after the largest noble gas, is a metal. It fits the criteria. Francium has a larger covalent and "Vander Waals" radius than Cesium, but Francium is an extremely unstable element and hence right now the prestige goes to Cesium.

In order to fit elements into his table, Newlands adjusted two elements in the same slot, but also put some unlike elements in the same slot.
  • a)
    True
  • b)
    False
Correct answer is option 'A'. Can you explain this answer?

Meera Rana answered
For example, cobalt and nickel were in the same slot and these were placed in the same column as fluorine, chlorine and bromine which have very different properties than these elements. Iron,which resembles cobalt and nickel in properties,had been placed far away from these elements.

According to IUPAC recommondations, the number of groups in the long form of the periodic table is :-
  • a)
    7
  • b)
    8
  • c)
    16
  • d)
    18
Correct answer is option 'D'. Can you explain this answer?

Krishna Iyer answered
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.

Which among the following elements has the largest atomic radii ?
  • a)
    Na
  • b)
    Mg
  • c)
    K
  • d)
    Ca
Correct answer is option 'C'. Can you explain this answer?

Raghav Bansal answered
Atomic radii increases as you move left to right or down the columns of the periodic table. Within a period of elements, each new electron is added to the same shell. When an electron is added, a new proton is also added to the nucleus, which gives the nucleus a stronger positive charge and a greater nuclear attraction. So as more electrons are added, the total radius of the atom increases. And so out of all the options, potassium (K) has the largest atomic radii.

Dobereiner’s triad arranged the elements with similar properties into:
  • a)
    Periods
  • b)
    Groups
  • c)
    Both period and group
  • d)
    None of these
Correct answer is option 'B'. Can you explain this answer?

Rohan Kapoor answered
For example, Dobereiner arranged groups of three elements with similar properties into 'triads'. Newlands and Mendeleev arranged the elements in order of increasing relative atomic mass.

Which of the following has lowest number of electrons in the valence shell ?
  • a)
    O
  • b)
    C
  • c)
    N
  • d)
    B
Correct answer is option 'D'. Can you explain this answer?

Pooja Shah answered
As we can see, the no. of electrons in the valence shell of oxygen (8) is => 6
In valence shell of carbon (6) => 4
In valence shell of Nitrogen (7) => 5
In valence shell of  boron (5) =>  3 
Therefore, boron has the lowest electron in the valence shell. 

 As we move from left to right in a period in modern periodic table, Atomic sizes of the elements generally
  • a)
     increaseq
  • b)
    decrease
  • c)
     remain same
  • d)
    approach zero
Correct answer is option 'B'. Can you explain this answer?

Rahul Kapoor answered
In a period, more electrons are added to the same shell as we go from left to right because the atomic number increases. This also increases the attraction between electrons and protons and that's why atomic size decreases. Increasing nuclear charge pulls the electrons closer to the nucleus.

An element has an atomic number of 15 with which of the following elements will it show similar chemical properties.        
  • a)
    Be (4)        
  • b)
    Ne (10)        
  • c)
    N(7)        
  • d)
    O (8)
Correct answer is option 'C'. Can you explain this answer?

Krishna Iyer answered
The valence electrons of the atomic number 15 has 5 electrons in its outermost shell . Nitrogen also has 5 electrons in it's outer shell. It also belongs to 15 th group and has same chemical properties, others  have 2,8 and 6 in their outermost shell. 

Nitrogen and phosphorus belong to the group 15 of the periodic table. Which of these will be more electronegative?
  • a)
    Phosphorus
  • b)
    Both are equally electronegative
  • c)
    Nitrogen
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Arun Yadav answered
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements.

Mendeleev’s classification was based on _______ .
  • a)
    Increasing atomic mass
  • b)
    Decreasing atomic number
  • c)
    Increasing atomic number
  • d)
    Decreasing atomic mass
Correct answer is option 'A'. Can you explain this answer?

Krishna Iyer answered
Mendeleev's Periodic Law states that the properties of elements are the periodic function of their relative atomic masses. Mendeleev arranged all 63 elements; which were discovered till his time; in the order of their increasing relative atomic masses in a tabular form. It is known as Mendeleev's Periodic Table.

Newlands classification of elements did not include _______ .
  • a)
    Metalloids
  • b)
    Metals
  • c)
    Noble gases
  • d)
    Non-metals
Correct answer is option 'C'. Can you explain this answer?

Arun Yadav answered
Noble gases were not found as and could not be a part of Newland's law of octaves, as:

1. These gases are inert and do not react with any other element.

2. These gases are found in nature in very small proportions.

Which group of periodic table does Ge belongs to ?
  • a)
    12 group
  • b)
    11 group
  • c)
    13 group
  • d)
    14 group
Correct answer is option 'D'. Can you explain this answer?

Anjana Khatri answered
The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). In modern IUPAC notation, it is called Group 14.

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