MCQ
Q.
Modern Periodic table is based on _____.
Correct Answer: C
The correct answer is option 3 i.e. the Atomic Number
- The periodic table is based on Atomic Number.
- The atomic number is the number of protons found in the nucleus of every atom of that element.
- The periodic table is managed by the International Union of Pure and Applied Chemistry, or IUPAC.
- In 1869, Dimitri Mendeleev included 63 known elements arranged according to increasing atomic weight. But there were many elements he could not place in the periodic table and with the discovery of new noble elements, there was a need to arrange the elements. Henry Moseley later arranged the elements in the periodic table by their number of protons rather than their atomic weights.
- The modern periodic table orders the elements according to increasing atomic number rather than increasing atomic weight.
- There are 118 elements in a periodic table. There are seven periods and eighteen groups in the modern periodic table.
- On moving from left to right in a period, the size of atoms(atomic size) decreases.
- On moving from left to right in a period, the metallic character of elements decreases, whereas the non-metallic character increases.
- While going down in a group of the periodic table, the size of atoms increases (or atomic size increases).
- While going down in a group of the periodic table, the metallic character of elements increases.
- Electronegativity and reactivity of non-metals increase along the period and decrease down the group.
