The Atom and also Electromagnetic Radiation

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Fundamental Subatomic Particles Electromagnetic Radiation
Light and Other develops of Electromagnetic Radiation

Particle Symbol Charge Mass
electron e- -1 0.0005486 amu
proton p+ +1 1.007276 amu
neutron no 0 1.008665 amu

The variety of protons, neutrons, and also electrons in one atom deserve to be established from a set of an easy rules.

The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is same to the amount of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass variety of the atom (M) and also the atom number (Z).

Examples: Let"s determine the number of protons, neutrons, and also electrons in the complying with isotopes.

12C 13C 14C 14N

The various isotopes of an element are identified by creating the mass variety of the atom in the top left edge of the symbol because that the element. 12C, 13C, and also 14C are isotopes the carbon (Z = 6) and therefore contain six protons. If the atoms space neutral, they additionally must contain six electrons. The just difference between these isotopes is the number of neutrons in the nucleus.

12C: 6 electrons, 6 protons, and also 6 neutrons

13C: 6 electrons, 6 protons, and also 7 neutrons

14C: 6 electrons, 6 protons, and 8 neutrons

Practice problem 1:

Calculate the variety of electrons in the Cl- and Fe3+ ions.

Click here to inspect your answer come Practice trouble 1

Electromagnetic Radiation

Much the what is known about the structure of the electrons in an atom has actually been acquired by studying the interaction in between matter and different creates of electromagnetic radiation. Electromagnetic radiation has some of the nature of both a particle and also a wave.

Particles have actually a definite mass and they accounting space. Waves have no mass and yet they bring energy together they travel with space. In addition to their capability to lug energy, waves have four other characteristics properties: speed, frequency, wavelength, and also amplitude. The frequency (v) is the number of waves (or cycles) every unit of time. The frequency of a tide is reported in units of cycles per 2nd (s-1) or hertz (Hz).

The idealized drawing of a wave in the figure listed below illustrates the definitions of amplitude and also wavelength. The wavelength (l) is the the smallest distance between repeating point out on the wave. The amplitude of the tide is the distance in between the highest possible (or lowest) allude on the wave and also the facility of gravity of the wave.


If we measure the frequency (v) the a wave in cycles per second and the wavelength (l) in meters, the product the these two numbers has the systems of meters every second. The product the the frequency (v) time the wavelength (l) that a tide is as such the rate (s) in ~ which the wave travels through space.

vl = s

Practice problem 2:

What is the speed of a wave that has actually a wavelength of 1 meter and a frequency the 60 cycles every second?

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Practice trouble 3:

Orchestras in the United says tune their tools to one "A" that has a frequency that 440 cycles every second, or 440 Hz. If the speed of sound is 1116 feet per second, what is the wavelength the this note?

Click here to check your answer come Practice problem 3

Click here to see a solution to Practice problem 3

See more: What Does Bbl Mean In Text Language, Definition Of Bbl

Light and also Other develops of Electromagnetic Radiation

Light is a wave with both electric and also magnetic components. That is thus a form of electromagnetic radiation.

Visible light consists of the small band of frequencies and also wavelengths in the section of the electro-magnetic spectrum that our eyes deserve to detect. It includes radiation through wavelengths between around 400 nm (violet) and also 700 nm (red). Because it is a wave, irradiate is bent when it beginning a glass prism. Once white light is focused on a prism, the light rays of different wavelengths room bent through differing amounts and the irradiate is transformed into a spectrum that colors. Beginning from the next of the spectrum where the light is bent by the smallest angle, the colors space red, orange, yellow, green, blue, and violet.

As we deserve to see from the adhering to diagram, the energy carried by light boosts as us go from red come blue throughout the visible spectrum.


Because the wavelength the electromagnetic radiation have the right to be as long as 40 m or as brief as 10-5 nm, the clearly shows spectrum is only a small portion of the total selection of electromagnetic radiation.


The electromagnetic spectrum contains radio and also TV waves, microwaves, infrared, clearly shows light, ultraviolet, x-rays, g-rays, and cosmic rays, as presented in the figure above. These various forms the radiation all travel at the rate of irradiate (c). They differ, however, in your frequencies and wavelengths. The product of the frequency time the wavelength the electromagnetic radiation is constantly equal to the rate of light.

vl = c

As a result, electromagnetic radiation that has actually a lengthy wavelength has a low frequency, and radiation through a high frequency has a quick wavelength.

Practice trouble 4:

Calculate the frequency that red light that has a wavelength of 700.0 nm if the rate of light is 2.998 x 108 m/s.