List key elements that lead to variations in the physical and chemical conditions of different habitats.

What is the difference between physical and chemical adsorptions?

Why do elements in the same group have similar physical and chemical properties ?

How does lanthanoid contraction affect the physical and chemical properties of the elements of lanthanoid series ?

What are the two main components of an ecosystem? Discribe the physical factors which affect the distribution of organisms in different habitats.

In the modern periodic table, calcium (atomic number20) is surrounded by element with atomic number 12,19,21 and 38 which of these have physical and chemical properties resembling calcium?