Question

Pls answer the below

Answer 1

Answer:

1) 17

since the atomic number of a element denotes the number of protons present in it.

2) 21

     mass of E = 18 + 22 (protons + neutrons) = 40

     mass of B = 9 + 10 = 19

     difference of E & B = 40 -19 = 21

3) A-2, D-18

Since a cation is a positive atom, that means A has to lose an electron to stabilize.

Since a anion is a negative atom, that means D has to gain an electron to form octet valancy in its outermost shell.

4) 2,8

number of electrons in C = 13

$C^+^3$  means that it lost 3 electrons, so the number of electrons in C is now 13 - 3 = 10.

the electron distribution will be-

K=2 , L=8.