Question

1.- a)What experimental evidence leads scientists to believethat only "quantized" electronic energy states exist in atoms? b)What is the λ (wavelength) range of the visible spectrumfor electromagnetic radiation? c) What is the color of the"short" λ end of the visible spectrum? d) Ifa substance absorbed the λ from the "short" λ end of thevisible spectrum, what would be its color?

2.- Since FeNCS²⁺ has an absorption maximum at 447nm, what is the color of the FeNCS²⁺ ion insolution?

3.- Explain why, "roses are red and violets are blue".

Answer 1

1)

a) Photoelectric effect. A threshold frequency was required forphotons (threshold frequency requires threshold energy) for an atomto emit an electron. This clashed with classical thought, becauseit was frequency, not intensity, that determined ionization.

b) 400 - 700 nm

c) violet (small wavelength, large frequency)

d)

It would absorb violet, which has a complementary color of yellow.It would appear yellow

2)

Blue has a wavelength of 440-490 nm. So FeNCS2+ absorbs blue.

Blue's complementary color is orange. It appears orange.

3) Roses absorb the color complementary to red (green).
Violets absorb orange light, so they appear blue

Answer 2

2)

Blue has a wavelength of 440-490 nm. So FeNCS2+ absorbs blue.

Blue's complementary color is orange. It appears orange.

3) Roses absorb the color complementary to red (green).
Violets absorb orange light, so they appear blue