The question refers to the elements of the periotic table with atomic number from 3 to 18.

Which of these:
is/are noble gas?
is a halogen?
is an alkali metal?
Write the electron configuration of G.
If A combines with F, what would be the formula of resulting compound?

Write the names and symbols of two most reactive metals belongiong to group I of the periodic table. Explain by drawing electronic structure how either one of the two metals reacts with halogen. With which name is the bond formed between these elements known and what is the class of the compuond so formed known? state any four physical properties of such compounds.

Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern perioidic table to these two elements belong? What type of bond will be formed between them and why?

Agreat physicist of this century (RA.M. Dirac) loved playing with numerical values of Fundamental constants of nature. This led him to an interesting observation. Dirac found that from the basic constants of atomic physics (c, e, mass of electron, mass of proton) and the gravitational constant G, he could arrive at a number with the dimension of time. Further, it was a very large number, its magnitude being close to the present estimate on the age of the universe (~15 billion years) . From the table of fundamental constants in this book, try to see if you too can construct this number (or any other interesting number you can think of). If its coincidence with the age of the universe were significant, what would this imply for the constancy of fundamental constants ?

An atom has electronic configuration 2,8,7. To which of the following element would it be chemically similar?(atomic number are given in following N(7),F(9),Ar(18)