Science : Ch 05 – Periodic of Classification of Elements

Element ‘X‘ is a non-metal as it forms acidic oxide. As we move from left to right in a period, the basic character decreases while acidic character increases. Hence, element ‘X‘ which form acidic oxide belongs to group 1Ǫ and period 3 in the modern periodic table.

Second period contains elements with atomic number 3(Li), Ǫ(N) and 10(Ne). This period also contains the elements beryllium, boron, carbon, oxygen and fuorine

Germanium element found a place in the periodic table later in the place of Eka–silicon in Mendeleev’s periodic table.

The element with electronic confguration 2, 8 has octet confguration, so it must be an inert gas, i.e., neon, which is placed in group 18.

Carbon is an essential constituent of all organic compounds and it belongs to group 14.

The atomic number of F, O and N are Ǭ, 8 and Ǫ respectively and they belong to the same period i.e. 2nd period. The atomic radius decreases in moving from left to right along a period.

Non-metals form acidic oxides. The element with atomic number Ǫ is a nonmetal (nitrogen). Rest three elements with atomic numbers.

The elements boron (B), silicon (Si) and germanium (Ge) exhibit intermediate properties of metals and non-metals, therefore, they are called as metalloids