Question

X
Y
Protons
17
17
4. The composition of nuclei of two atomic species X and Y are given below.
(i) Find the mass number of X and Y. State the relationship
between X and Y.
(ii) The K and L shells of an atom are completely filled. State
the name of this element.
nucontion to alectronic configuration ?
Neutrons
18
20
TT 71​

Answer 1

Answer:

a) Mass number = No. of protons + No. of neutrons

So, mass number of X = 17 + 18 = 35

Mass number of Y = 17 + 20 = 37

X and Y are isotopes of same element since number of protons is same (same atomic number) in both.

(b) Numbers of electrons = 6 since:

K

L

2

4