Name:

(a) three elements that have a single electron in their outermost shells.

(b) two elements that have two electrons in their outermost shells.

(c) three elements with filled outermost shells.

Compare and contrast the arrangement of elements in Mendeleev's periodic table and the Modem periodic table.

In the modem periodic table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium ?

The elements of a period of the periodic table are given in order from left to right with one of its element missing:

a. To which period do these elements belong?

b. One element of this period is missing. Which is the missing element and where should it be placed?

c. Which one of these elements in this period shows the property of catenation?

d. Which one of these elements is least reactive?

The position of some elements A,B,C,D,E,F and G in the Modern Periodic Table is given as under:

a. In which group are inert elements placed?

b. What type of ions would B, C, E and F form?

c. Which elements would have chemical properties similar to C?

d. How many shells would A have?

e. What is the similarity between A and D?

f. Identify the most abundant element in the earth’s crust.