Chemistry Multiple Choice Questions on “Electronic Configurations of Elements and the Periodic Table”.
1. The electrons’ distribution into the atomic orbitals is called as _________
a) Electronic order
b) Electronic distribution
c) Electronic filing
d) Electronic configuration
Answer: d
Clarification: When electrons are distribution into the orbitals of the atoms by following Aufbau’s principal, Hund’s rule maximum multiplicity and Pauli’s exclusive principle, the order they are filled is represented by the electronic configuration.
2. The location of any element in the periodic table is determined by the __________ of the filled last orbital.
a) Spin quantum number
b) Quantum numbers
c) Azimuthal quantum number
d) Magnetic quantum number
Answer: b
Clarification: Quantum numbers are responsible for an element’s position in the periodic table. For example, as we know the principal quantum number defines the main energy level i.e. shell. The last orbital principal quantum number is the periodic number of the element.
3. How many electrons are there in the L-shell of Boron?
a) 3
b) 2
c) 1
d) 4
Answer: a
Clarification: The atomic number of Boron is 5 and it contains two elements in the K-shell and three elements in the L-shell as well as 4 electrons in s-orbital and 1 electron and p-orbital. The element preceding Boron is beryllium and the element succeeding Boron is carbon.
4. What are the d-block elements called?
a) Inner transition elements
b) Alkali earth metals
c) Transition elements
d) Noble gases
Answer: c
Clarification: The d-block elements are called transition elements as the electrons are energetically filled. The exact meaning of transition elements is that elements have either partially or fully filled subshell or can actively cations by losing electrons.
5. 3d transition series starts from _________ and ends with __________
a) Zinc, Scandium
b) Scandium, Zinc
c) Vanadium, Nickel
d) Argon, Zinc
Answer: b
Clarification: In the 3d transition series, the have either partially or fully filled 3d orbitals. The 3d transition state starts from Scandium (Z = 21) having electronic configuration as 3s23d1 and ends with Zinc (Z = 30) whose electronic configuration is 3s23d10.
6. Which block elements are known as inner transition elements?
a) s-block
b) p-block
c) d-block
d) f-block
Answer: d
Clarification: Inner transition elements are f-block i.e. 4f and 5f. They include elements from 57 to 71 and 89 to 103. The 4f elements are lanthanoids (57 – 71) and 5f are actinides (89 – 113). Most of the actinides are radioactive.
7. The Lanthanoid series is the same as the Actinoid series.
a) True
b) False
Answer: b
Clarification: Both the Lanthanoid series and the Actinoid series make up Inner transition elements, but they are not the same. The 4f elements are lanthanoids (Z = 57 to Z = 71) and 5f are actinides (Z = 89 to Z = 113).
8. Write the correct electronic configuration of Neon.
a) 1s22s22p6
b) 1s22s2
c) 1s22p6
d) 2s22p6
Answer: a
Clarification: Neon is made up of 10 electrons. As per Aufbau’s principle, orbitals with lower energy must be filled first and s-orbital can only accommodate 2 electrons while p can accommodate 6 electrons. So the electronic configuration of Neon is 1s22s22p6.
9. Group I elements are called as ________
a) Alkali metals
b) Noble gases
c) Chalcogens
d) Halogens
Answer: a
Clarification: Group I elements are known as Alkali metals as they have a great ability to form strong bases i.e. alkalies. Alkalies are the strong bases with the ability to neutralize strong acids. They consists of Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Cesium(Cs) and Francium(Fr).
10. The fourth period ends with the element ________
a) Helium
b) Argon
c) Neon
d) Krypton
Answer: d
Clarification: Every period ends with a noble gas, as the element at the end of the period is with the fully filled orbitals. The 4th period has an outer shell as O i.e. n = 4. So the configuration is [Ar}4s23d104p6, that is Krypton.