In diagonal relationship, which element is related to Be?

Diagonal relationship in shown by

Show that the relation R in the set of integers given by R={(a,b):4" divides "a-b} is an equivelence relation. Find the set of all elements related to 0.

Show that the relation R in the set Z of integers given by R{(x,y):6" divides "x-y} is an equivalence relation. Find the set of all elements related to 0.

Show that the relation R in the set A={x in Z:0lexle12} given by R={(a,b):|a-b|" is multiple of "4} is a equivalence relation. Find the set of all elements related to 1.

Which relation is correct?

Give an example of a relation which is reflexive but not symmetric.

Which element is more reactive - lead or copper?

In the first transition series of elements, which element shows highest oxidation state?