Calculate energy of photons emitted by 0.312 g Na  with the wavelength 587 nm. Na = 22.99 g/ mole  a) 2.77 kJ b) 1.72 x 10^-19 kJ c) 1072 kJ d) 9.21 kJ

What is the energy of photon that causes a hydrogen atom to undergo a transition from n-1→ n=2? State your answer in electronvolts (eV) (without units) to three significant figures. Note: 1 eV= 1.602 x 10-19 J.

2. A laser pointer used in the classroom emits light at 6550 A, at a power of 4.00 mW. (One watt is the SI unit of power, the measure of energy per unit of time. 1 W = 1 J/s). How many photons are emitted from the pointer in 115 seconds?

What is the wavelength of light (in nm) emitted when an electron transitions from n = 5 to n = 2 in a hydrogen atom? Submit an answer to three significant figures.

A photon of radiation has a frequency of 4.64 x 108 Hz. Calculate its wavelength (in nm) and energy in J

4) A sodium lamp emits yellow light with a wavelength of 589 nm. What is the energy, E, in kJ/mol of this light? Use h= 6.626 x 10-³4 J s c = 2.998 x 10⁰ m s-¹ N₁ = 6.022 x 1023 mol-¹

3. A student was asked to write the electron configuration for a number of elements on an exam. Here is a sample of some of their answers: a) Ne s2 b) 1s²25³ c) [Kr] 4s1 Select any 2 of the answers above, and explain what is wrong. What element do you think they were describing? Write the correct electron configuration for that element.

Calculate the wavelength?