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Chemistry (Part-II)

📆 October 28, 2024

Total Questions: 54

31. Periodic table was first given by whom? [S.S.C. Online MTS (T-I) 20.09.2017]

Correct Answer: (c) Dmitry Mendeleev
Solution:Mendeleev was the first to classify the elements in the form of the periodic table and this classification was based on the atomic mass of the elements. Later, a scientist named Mosley revised Mendeleev's periodic table and classified the elements on the basis of their atomic number, which is known as the 'Modern periodic table'.

32. Who invented the modern periodic table? [S.S.C. Online CHSL (T-I) 11.01.2017]

Correct Answer: (b) Mendeleev
Solution:Mendeleev was the first to classify the elements in the form of the periodic table and this classification was based on the atomic mass of the elements. Later, a scientist named Mosley revised Mendeleev's periodic table and classified the elements on the basis of their atomic number, which is known as the 'Modern periodic table'.

33. Which scientist arranged the Periodic Table of Elements in the order of increasing atomic masses? [S.S.C. Online CHSL (T-I) 13.10.2020]

Correct Answer: (d) Dmitri Mendeleev
Solution:Russian scientist Dmitry Mendeleev, expressing his opinion regarding the classification of elements, gave a rule, which is called Mendeleev's periodic law. According to this, the physical properties of the elements and their chemical properties are periodic functions of their atomic masses (or atomic mass).

34. What is the common characteristic of the same group elements in the periodic table? [S.S.C. Online Graduate Level (T-I) 11.08.2017]

Correct Answer: (a) Electrons in the outermost shell
Solution:Elements in the same group as in the periodic table have the same number of electrons in the outermost shell of the atom. For example, the elements of the Ist group, Na and K, etc. have one electron in their outermost shell.

35. Who among the following gave the 'Periodic Law'? [S.S.C. Online C.P.O.S.I. (T-I) 1.07.2017]

Correct Answer: (d) Dmitry Mendeleev
Solution:
Dmitry Mendeleev is credited with giving the 'Periodic Law', which originally stated that the properties of elements are a periodic function of their atomic masses. The modern Periodic Law states that the properties of elements are a periodic function of their atomic numbers.

36. As per Newlands Octaves, which of the following has the same properties as sodium? [S.S.C. Online M.T.S. (T-I) 14.10.2021]

Correct Answer: (d) Lithium
Solution:

According to Newlands' Law of Octaves, every eighth element has similar properties. Starting from Lithium (Li): 

  1. Li
  2. Be
  3. B
  4. C
  5. N
  6. O
  7. F
  8. N

So, Lithium has similar properties to Sodium according to Newlands' Octaves. 

37. The modern periodic table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 2nd group and the 4th period? [S.S.C. Online CHSL (T-I) 7.02.2017]

Correct Answer: (a) 20
Solution:The 2nd group is the alkaline earth metals. The 4th period contains elements with electrons in the 4th energy level. The element in the 2nd group and 4th period is Calcium (Ca), which has an atomic number of 20.

38. There are 18 groups and 7 periods in the modern periodic table. What is the atomic number of the element which is placed in the 4th group and 4th period? [S.S.C. Online CHSL (T-I) 31.01.2017]

Correct Answer: (c) 22
Solution:The 4th group contains elements in the d-block (transition metals). The 4th period starts with Potassium (Group 1) and Calcium (Group 2), followed by Scandium (Group 3). The element in the 4th group and 4th period is Titanium (Ti), which has an atomic number of 22.

39. The horizontal rows in the modern periodic table are called: [S.S.C. Online CGL (T-I) 23.08.2021]

Correct Answer: (d) Periods
Solution:The horizontal row in the modern periodic table are called 'Periods' and the vertical column are called 'Groups'. There are 18 Groups and 7 periods in this table.

40. In the periodic table, moving from left to right in a period, there are the same number of: [S.S.C. Online C.P.O.S.I. (T-I) 7.07.2017]

Correct Answer: (c) Shells
Solution:

In the periodic table, moving from left to right in a period, there are the same number of  Shells. All elements in the same period have their valence electrons in the same principal energy level (shell), although the number of valence electrons increases across the period.

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