Railway Science (Chemistry-Periodic Table) (Part-VI)

Total Questions: 50

1. ______ is not a transition metal. [RRB Group D 16/10/2018 (Morning)]

Correct Answer: (a) Np
Solution:

It is the first transuranic element and Its atomic number is 93. Transition metals: These are elements in the d-block of the periodic table, characterized by partially filled d electron orbitals. Zr (zirconium), Tc (technetium), and Re (rhenium) are transition metals.

2. In Mendeleev's periodic table, which of the following elements found a place in the table later ? [RRB Group D 16/10/2018 (Morning)]

Correct Answer: (b) Sc, Ga and Ge
Solution:

Scandium (Symbol Sc, Atomic number 21) was discovered in 1879, gallium (Symbol Ga, Atomic number 31) in 1875, and germanium (Symbol Ge, Atomic number 32) in 1886, after Mendeleev had already published his periodic table. Mendeléev’s Periodic Table was published in a German journal in 1872.

3. In 2nd and 3rd period is : [RRB Group D 16/10/2018 (Afternoon)]

Correct Answer: (a) 8 elements
Solution:

2nd period: Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), and Neon (Ne). 3rd period: Sodium (Na), Magnesium (Mg), Aluminum (Al), Silicon (Si), Phosphorus (P), Sulfur (S), Chlorine (Cl), and Argon (Ar).

4. Name the group of modern periodic tables in which all the elements are gasses? [RRB Group D 16/10/2018 (Afternoon)]

Correct Answer: (a) Group 18
Solution:

This group is also known as the noble gasses or the inert gasses. It includes the following elements: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn).

5. The 4th and 5th periods contain: [RRB Group D 16/10/2018 (Evening)]

Correct Answer: (b) 18 elements
Solution:

1st period: 2 elements (Hydrogen and Helium). 2nd period: 8 elements (Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon). 3rd period: 8 elements (Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, Argon).

6. An element having atomic number 17 will resemble which of the following elements having Atomic number as given below! [RRB Group D 16/10/2018 (Evening)]

Correct Answer: (d) 35
Solution:

In the periodic table, Elements in the same group generally share similar chemical properties due to having the same number of valence electrons. For example, an element with atomic number 17 falls in Group 17 (halogens).

7. Where would you locate the element with electronic configuration 2, 8, 3 in the Modern Periodic Table ? [RRB Group D 22/10/2018 (Morning)]

Correct Answer: (b) Period 3
Solution:

This is because the element with electronic configuration 2, 8, 3 has 13 electrons, which is the same as the atomic number of aluminum (Al). Aluminum is located in period 3, group 13 of the modern periodic table.
The period number corresponds to the highest principal quantum number (n) of the element’s electrons, and the group number corresponds to the number of valence electrons in the element’s outermost shell.

8. ______ is the most metallic element in the fifth period. [RRB Group D 22/10/2018 (Afternoon)]

Correct Answer: (a) Rubidium
Solution:

Metallic character: In general, metallic character decreases across a period (left to right) in the periodic table. This means elements on the left side of a period exhibit more metallic properties like conductivity, malleability, and ductility compared to those on the right.

9. In the Mendeleev periodic table, gaps were left for the undiscovered elements. Which of the following elements found a place in the periodic table later ? [RRB Group D 22/10/2018 (Afternoon)]

Correct Answer: (c) Ge
Solution:

It was undiscovered at the time of Mendeleev's table creation. Based on the gaps and trends in the table, Mendeleev predicted the properties of an element he called "eka-silicon" that would fill the gap between silicon and tin.

10. Which of the following pairs of elements with atomic numbers belong to the same group? [RRB Group D 22/10/2018 (Evening)]

Correct Answer: (a) 13 and 31
Solution:

Element with atomic number 13 is Aluminum (Al), which belongs to group 13 (also known as group IIIA). Element with atomic number 31 is Gallium (Ga), which belongs to group 13.