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

Total Questions: 49

1. Chlorine, fluorine and iodine are examples of ________. [RRB Group D 1/12/2018 (Afternoon)]

Correct Answer: (c) halogen
Solution:

They belong to Group 17 (Group VIIA) and include Fluorine (F₉), Chlorine (Cl₁₇), Bromine (Br₃₅), Iodine (I₅₃), and Astatine (At₈₅). These elements are characterized by having seven valence electrons.

2. Which of the following metals forms positively charged ions more readily? [RRB Group D 3/12/2018 (Evening)]

Correct Answer: (a) sodium
Solution:

It readily forms positively charged ions (cations) by losing one electron. It’s an electropositive metal. Sodium (Na): atomic number - 11, melting point: 97.794°C, boiling point: 882.940°C.

3. Which of the following is NOT an Alkaline Earth Metal? [RRB Group D 4/12/2018 (Afternoon)]

Correct Answer: (d) Sodium
Solution:

Sodium belongs to Group 1 of the periodic table (alkali metals). Alkaline earth metals are a group of chemical elements that belong to Group 2 of the periodic table. This group includes Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).

4. Which of the following options is correct for two elements having similar chemical properties? [RRB Group D 05/12/2018 (Morning)]

Correct Answer: (a) The elements will have the same number of valence electrons.
Solution:

The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties.

5. The ionization energy of an element depends on ______. [RRB Group D 06/12/2018 (Evening)]

Correct Answer: (a) Nuclear charge
Solution:

Ionization energy, also called ionization potential, is the amount of energy required to remove an electron from an isolated atom or molecule. The atomic number (Z) of an element is the number of protons in the nucleus of each atom of that element. Screening effect is reduction in the effective nuclear charge on the electron cloud, due to a difference in the attraction forces on the electrons in the atom.

6. What is the unit of ionization energy ? [RRB Group D 07/12/2018 (Afternoon)]

Correct Answer: (c) KJ mol⁻¹
Solution:

Ionization energy, also called ionization potential, is the amount of energy required to remove an electron from an isolated atom or molecule. Pressure is defined as force applied per unit area. SI unit of Pressure - Pascal (1 Pascal = N/m² ). Joule is the SI unit of Energy.

7. _______ is the free energy released when an electron is added to its neutral gaseous atom. [RRB Group D 10/12/2018 (Evening)]

Correct Answer: (c) electron affinity
Solution:

Electron affinity is the ability of an atom to accept an electron. It increases from left to right within a period and decreases from top to bottom within a group. Ionization energy is the energy required to remove an electron from a neutral atom in its gaseous phase. Electronegativity is a chemical property describing an atom's ability to attract and bind with electrons.

8. How many groups are there in Mendeleev's periodic table ? [RRB Group D 10/12/2018 (Evening)]

Correct Answer: (a) 8
Solution:

Mendeléev’s Periodic Table contains vertical columns called ‘groups’ and horizontal rows called ‘periods’. The elements were arranged into 7 horizontal rows known as periods and 8 vertical columns known as groups. Dmitri Mendeleev discovered the periodic table in February of 1869.

9. Lanthanide and Actinide: [RRB Group D 11/12/2018 (Afternoon)]

Correct Answer: (c) f-block element
Solution:

It consists of the two series, lanthanoids (the fourteen elements following lanthanum) and actinoids (the fourteen elements following actinium). The f-block is placed outside at the bottom of the periodic table and in elements of this block 4f and 5f orbitals are progressively filled.

10. If the atomic number of an element is 8, what will be its electronic configuration ? [RRB Group D 12/12/2018 (Morning)]

Correct Answer: (a) 2 , 6
Solution:

Oxygen (O) is a chemical element with an atomic number of 8 (it has eight protons in its nucleus). The electron configuration of oxygen is 1s²2s²2p⁴ .