Answer:
Following are the response to the given question:
Explanation:
The number of shells
n = 4
Calculating the spectral line:

Explanation:
balance the equation ...HCl,Ba(OH) and BaCl2 are aqueous
know groups of the elements H 1+ ,Cl -,Ba 2+,OH-
write complete ionic eqution and eliminate spectator ions those appearing on both sides Cl and Ba