Question

In the following table, six elements A, B, C, D, E and F (here letters are not the usual symbols of the elements) of the modern periodic table with their atomic numbers are given.

3 A	4	5	6	7	8E	9	10 G
11 B	12 C	13	14 D	15	16	17 F	18

i. Which of these is a noble gas? 

ii. Which of these is a halogen? 

iii. If B combines with F, what would be the formula of the compound formed? 

iv. Write the electronic configuration of C and E.

Answer 1

i. G is a noble gas (Neon) because its electronic configuration is (2,8). 

ii. F is a halogen (chlorine) because its atomic number is 17 and electronic configuration is (2,8,7). 

iii. B with atomic number 11 will have electronic configuration (2,8,1) i.e. Na. F with atomic number 17 will have electronic configuration (2,8,7) i.e. Cl.  Compound formed will have formula BF i.e. NaCl.

iv. Electronic configuration of C = (2,8,2) and that of E = (2,6).