Calculate the wavelength of the light emitted when an electron in a hydrogen atom makes each transition and indicate the region of the electromagnetic spectrum (infrared, visible, ultraviolet, etc.) where the light is found. J., Tro Nivaldo. Chemistry (p. 346). Pearson Education. Kindle Edition.

The question is incomplete, the complete question is;

Calculate the wavelength of the light emitted when an electron in a hydrogen atom makes each transition and indicate the region of the electromagnetic spectrum (infrared, visible, ultraviolet, etc) where the light is found.

(a) n=2  →  n=1

(b) n=3  →  n=1

(c) n=4  →  n=2

(d) n=5  →  n=2

see explanation

Explanation:

From;

ΔE = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

a)

-2.18 * 10^-18 J (1/1^2 - 1/2^2)

= -2.18 * 10^-18 J *3/4

=- 1.64 * 10^-18 J

obtain wavelength from;

λ = hc/E

h= 6.6 * 10^-34Js

c= 3 *10^8 m/s

λ = 6.6 * 10^-34 * 3 *10^8 /1.64 * 10^-18

λ = 12.1* 10^-8 m

This belongs to the ultraviolet region

b)-2.18 * 10^-18 J (1/1^2 - 1/3^2)

= -2.18 * 10^-18 J *8/9

=- 1.94 * 10^-18 J

obtain wavelength from;

λ = hc/E

h= 6.6 * 10^-34Js

c= 3 *10^8 m/s

λ = 6.6 * 10^-34 * 3 *10^8 /1.94 * 10^-18

λ = 10.2 * 10^-8 m

This belongs to the ultraviolet region

c)-2.18 * 10^-18 J (1/2^2 - 1/4^2)

= -2.18 * 10^-18 J *3/16

=- 4.1 * 10^-19 J

obtain wavelength from;

λ = hc/E

h= 6.6 * 10^-34Js

c= 3 *10^8 m/s

λ = 6.6 * 10^-34 * 3 *10^8 /4.1 * 10^-19

λ = 4.83* 10^-7 m

This belongs to the visible region

d) -2.18 * 10^-18 J (1/2^2 - 1/5^2)

= -2.18 * 10^-18 J *21/100

=- 4.58 * 10^-19 J

obtain wavelength from;

λ = hc/E

h= 6.6 * 10^-34Js

c= 3 *10^8 m/s

λ = 6.6 * 10^-34 * 3 *10^8 /4.58 * 10^-19

λ = 4.32* 10^-7 m

This belongs to the visible region

where is the following

explanation:

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.