Class 10 Science Chapter 5 MCQ for 2020-2021
| Class: 10 | Science |
| Chapter: 5 | Multiple Choice Questions (MCQ) Tests |
Class 10 Science Chapter 5 MCQ with Answers
MCQ tests practice for class 10 science is given below. Here, you can practice chapter 5 of class 10 science with important MCQs related to NCERT Textbook. Class 10 Science Chapter 5 MCQs are given below with answers and explanation.
Q1
Lavish appeared in class test but he confused to know the correct statement. Would you help him to know that?
[A]. The elements calcium, strontium and barium were put in one group called alkaline earth metal group or alkaline.
[B]. The elements calcium, strontium and barium have similar chemical properties and form a triad.
[C]. The elements calcium, strontium and barium have a valency of 2 (they are divalent).
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q2
Newlands’ law of octaves for the classification of elements had the following limitations. Choose the correct limitation:
[A]. Newlands assumed that only 56 elements existed in nature and no more elements would be discovered in the future.
[B]. Newlands’ law of octaves was applicable to the classification of elements up to calcium only.
[C]. In order to fit elements into his table, Newlands put even two unlike elements having very different properties.
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q3
While working on the classification of elements, a Russian scientist Mendeleev found different things. Choose the correct one(s):
[A]. There were seven periods (horizontal rows) and eight groups (vertical columns) in the original periodic table of Mendeleev.
[B]. When elements are arranged in the order of increasing atomic masses, the elements with similar properties occur at regular intervals.
[C]. In order to make sure that the elements having similar properties fell in the same vertical column or group, Mendeleev left some gaps in his periodic table.
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are incorrect. Hence, your answer will be option [D].
Q4
Which of the following elements does not lose an electron easily?
[A]. Na
[B]. F
[C]. Mg
[D]. Al
Answer: Option B
Explanation:Smaller the atomic radius of an element, more difficult is lose electron. Among Na, F, Mg and Al, F has the smallest size. Also, it contains 7 electrons in its valence shell and it is most electronegative element. Hence, it does not lose an electron easily rather it gains electron easily.
Note: Elements of 2nd period have smaller size than those of the corresponding elements of the 3rd period. Further in a period, halogens have the smallest size. F belongs to 2nd period and rest three to 3rd period.
Q5
Which among the following elements has the largest atomic radii?
[A]. Ca
[B]. Na
[C]. Mg
[D]. K
Answer: Option D
Explanation:Na and K are in the same group and K is below than Na, so K will have higher atomic radius i.e., K > Na. In a period on moving from left to right, atomic radius decreases. Since, K and Ca are in the same period and K is in 1 group and Ca is in 2 group, so atomic radius of K will be more than Ca, i.e., K> Ca.
Also, Na and Mg are in the same period, but Na belongs to 1 group and Mg belongs to 2 group, so atomic radius of Na is more than Mg, i.e., Na > Mg. Thus, if we take all these together we get K > Na > Mg and K > Ca> Mg.
Hence, we can say the atomic radius of K largest.
Note: Atomic radii increases on moving down the group as new shell of electrons is added at each succeeding element.
Q6
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
Answer: Option D
Explanation:As we move from left to right in a period, the atomic number of each succeeding element increases by 1. So, the electrons are attracted close to the nucleus and hence, the atomic size decreases, along a period from left to right.
Therefore, the increasing order of radii is F, O, N as atomic number of F, O and N are 9, 8 and 7 respectively. Due to which F belongs to 17th group. O belongs to 16th group and N belongs to 15th group.
Note: Atomic radii is the distance between the centre of the nucleus and the outermost shell which contains electrons in an isolated system.
Q7
Pooja is writing some statements but she confused to know whether the statements are correct or not? If you know the answer to this question, then tell her:
[A]. The arrangement of elements in the modern (long form) periodic table is based on their electronic configurations.
[B]. The elements with atomic numbers 89 to 103 are called “lanthanide series”.
[C]. The number of elements in a period is fixed by the maximum number of electrons which can be accommodated in the various shells of an atom.
[D]. Scientist Neils Bohr who prepared modern periodic table of elements.
Answer: Option B
Explanation:The elements with atomic numbers 57 to 71 are called lanthanide series (because their first element is lanthanum). And the elements with atomic numbers 89 to 103 are called actinide series (because their first member is actinium).
Q8
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
Answer: Option B
Explanation:2nd period contains elements with atomic number 3(Li), 7(N), 10(Ne). Since, 2nd period has elements having atomic number 3 to 10.
Note: The number of elements in any period is fixed by the maximum number of electrons that can be accommodated in that particular shell. The maximum number of electrons that can be accommodated in any shell is given by the formula 2n2 where, n is the number of the given shell starting from the nucleus.
Q9
In Mendeleev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later?
[A]. Germanium
[B]. Chlorine
[C]. Oxygen
[D]. Silicon
Answer: Option A
Explanation:Mendeleev’s left some gaps in the periodic table for those elements which were not known at that time.
Germanium element found a place in the periodic table later and Mendeleev’s predictions were found to be remarkably correct.
Q10
Rahul is writing some statements about “Periodic Table”. Choose the correct one(s):
[A]. Elements having 6 valence electrons are placed in group 16.
[B]. Elements having 7 valence electrons are placed in group 17.
[C]. Elements having 8 valence electrons (or 2 valence electrons in K shell) are placed in group 18.
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
why did Mendeléev select Oxygen and Hydrogen to test the chemical properties of elements?
Mendeléev selected hydrogen and oxygen to test the chemical properties of elements as they are very reactive and formed compounds with most elements.
What were the limitations of Mendeleev’s Periodic Law?
1. Isotopes of all elements posed a challenge to Mendeleev’s Periodic Law.
2. The atomic masses do not increase in a regular manner in going from one element to the next. So it was not possible to predict how many elements could be discovered between two elements — especially when we consider the heavier elements.
3. No proper place assigned to Hydrogen.
What is modern periodic law?
The modern periodic law states that Properties of elements are a periodic function of their atomic number.
What happen to atomic radius of atoms when we move from left to right in a period?
The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.
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