1. Elements in the same column of the periodic table have:
a) Similar valence shell electron configuration
b) Same value of highest principal quantum number
c) Same number of nucleons
d) All of the mentioned
Answer: a [Reason:] The elements having similar valence shell electrons have similar chemical properties like reactivity, nature of bonds in their molecules etc. Hence in the modern periodic table, they were grouped in vertical columns called ‘groups’.
2. As we move down a group, electronegativity of elements generally:
c) Increases and then decreases
d) Decreases and then increases
Answer: a [Reason:] As we move down a group, atomic size increases which means that the valence electrons are much farther from the nucleus and hence experience less force of attraction. Hence the electronegativity decreases down the group.
3. How many periods are there in modern periodic table?
Answer: c [Reason:] Modern periodic table places elements having same maximum principal quantum number in one period. There are seven periods, though the seventh period consists many unstable artificial elements.
4. Temporary IUPAC systematic symbol for the synthetic element 117 is:
Answer: c [Reason:] IUPAC has assigned temporary systematic name Ununseptium [=Un(1) +un(1) + sept(7) + ium] to the element with atomic number 117. It belongs to group 17 of the periodic table and is predicted to be a halogen. As of 2015, its discovery has not been officially confirmed.
5. There are seventeen non-metals in the periodic table. Unlike metals in the same period, they have higher:
a) Atomic number
b) Atomic size
d) All of the mentioned
Answer: a [Reason:] Non-metals are located at the right end of their respective periods. As we move from left to right in a period or from top to bottom in a group, atomic number increases. Due to increasing charge on the nucleus, atomic size also decreases on moving right in a period. This is also the reason of increasing electronegativity or decreasing electropositivity.
6. d-block elements generally show multiple oxidation states. An exception to this is:
d) None of the mentioned
Answer: d [Reason:] Due to small increase in successive ionization enthalpies, most d-block elements exist in multiple oxidation states. However, Zn(I) compounds are very rare and the ion exists in dimeric form.
7. Uranium and Thorium are two important elements in nuclear power industry. In which block of the modern periodic table are they placed?
Answer: d [Reason:] Ground state Uranium and Thorium atoms have partially or totally empty 5f-orbitals. They are members of the actinide family and their naturally occurring isotopes are radioactive.
8. Moving down a group, which of the following properties generally diminishes?
b) Metallic character
c) Atomic radius
d) Molar mass
Answer: a [Reason:] Due to addition of one shell on moving down a group, the neighbourhood of the atom is better shielded by the electrons from attractive pull of the nucleus.
9. Radon is the sixth member of group 18 of the modern periodic table. Unlike other members of this group, Radon:
a) is solid near room temperature
b) is radioactive
c) possess high chemical reactivity
d) all of the mentioned
Answer: b [Reason:] Radon is a radioactive noble-gas at room temperatures. It is one of densest gases and the only naturally occurring radioactive gas. However, its daughter nuclei are solids. Not many compounds of Radon are known.
10. Ionization energy decreases down the group. It is the energy required by an isolated gaseous atom to form an anion.
Answer: b [Reason:] Ionization energy is the energy required by an isolated gaseous atom to lose the least tightly bound electron to form a cation. It decreases down the group as atomic size increases.
Synopsis and Project Report
You can buy synopsis and project from distpub.com. Just visit https://distpub.com/product-category/projects/ and buy your university/institute project from distpub.com