Express the frequency in inverse seconds. n=4--> n=3. can you tell me what formulas to use, because i have like 6 more of these to do and i can't figure it out.

Explanation:

When an electron jumps from one energy level to a lower energy level some energy is released in the form of a photon.

The difference in energy between the two levels is the energy of the photon and that energy is related to the frequency of the photon by the Einstein - Planck equation:

Where,

So, to find the frequency you must first find the energy.

The transition energy can be calculated using the formula:

Where E₀ = 13.6 eV ( 1 eV = 1.602×10⁻¹⁹ Joules) and n = 1,2,3,...

So, the transition energy between n = 4 and n = 3 will be:

Now you can use the Einstein - Planck equation:

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.