Question

c) How was discovery of isotopes proved to be a problem for Mendeleev’s
Periodic Table.

d) Define Valency.

e) Why aluminium oxide is called amphoteric oxide.​

Answer 1

Answer:

c)Mendeleev's periodic table was based on atomic masses.

isotopes of elements have same atomic number but different mass number.

d)valency: The combining capacity of an atom by sharing losing or gaining electrons is known as its valency.

e)Aluminium oxide is known as 'amphoteric oxide' due to its reaction with both acids and bases.

eg: It has reactions as both a base and an acid. Reaction with water: Aluminum oxide is insoluble in water and does not react like sodium oxide and magnesium oxide. The oxide ions are held too strongly in the solid lattice to react with the water.This reaction and others display the amphotericnature of aluminum oxide

Answer 2

Answer:

above answer is correct