Write the electronic configuration of the element ³⁵₁₇T.

(a) What is the group number of T?

(b) What is the period number of T?

(c) How many valence electrons are there in an atom of T?

(d) What is the valency of T?

(e) Is it a metal or a non-metal?

(f) State number of protons and neutrons in T.

In the periodic table, the elements of a same group have the same:

1. Number of valence electrons
2. Mass number
3. Atomic number
4. Number of electrons

All the members of group 15 have ……………. electrons in their outermost orbit.

1. 3
2. 7
3. 5
4. 8

Which of the following statements is correct with respect to the elements — Na, Mg, Al, Si, P, S and Cl.

1. Each element belongs to the same group.
2. Valency of each element is the same.
3. Each element belongs to the same period.
4. They are all metals.