Question

the electron in the atoms of four elements A,B,C and D are distributed in the three shells having 1,3,5 and 7 electrons in the outermost shell respectively. state the period in which these elements can be placed in the modern periodic table. write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.

Answer 1

hey there...
here is your answer...

period of elements A, B, C and D having 3shells will be 3rd in the modern periodic table as in modern periodic table, the no. of valence electrons state the group no. of the element and the no. of shells state the period no. .

electronic configuration of
A- K L M
2 8 1

D- K L M
2 8 7

molecular formula of A and D is AD or NaCl as A states the position of sodium(Na) and D states the position of chlorine(Cl).


Hope it helps : )

Answer 2

•A,B,C,D=3rd PERIOD ELEMENTS
•A=2,8,1
•D=2,8,7
•A=(Na)sodium
•D=(Cl)chlorine
•Na+Cl------>NaCl