Chemistry - Chapter 4

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the line emission spectrum of an atom is caused by the energies released when electrons

"jump from a higher energy level to a lower energy level

All forms of electromagnetic radiation move at a constant speed of

3.00 x 10^8 meters per second through a vacuum and at a slightly slower speeds through matter

what are the frequency and wavelength ranges of visible light?

400nm - 700nm

What is the speed of all forms of electromagnetic radiation in a vacuum?

All forms of electromagnetic radiation move at a constant speed of 3.00 × 10^8 meters per second (m/s) through a vacuum

Explain the mathematical relationship among the speed of electromagnetic radiation.

All forms of electromagnetic radiation move at a constant speed of 3.00 × 10^8 meters per second (m/s) through a vacuum and at slightly slower speeds through matter.

Substituting c/λ for v into the equation of energy gives the following:

E = hv, v = c/λ, E = hc/λ

one wave/second is called a

Hertz (Hz)

Describe the Bohr model of the hydrogen atom.

Niels Bohr proposed a hydrogen-atom model that linked the atom's electron to photon emission.The electron can circle the nucleus only in allowed paths, or orbits. The energy of the electron is higher when it is in orbits that are successively farther from the nucleus. When an electron falls to a lower energy level, a photon is emitted, and the process is called emission. Energy must be added to an atom in order to move an electron from a lower energy level to a higher energy level. This process is called absorption.

Max Planck proposed that the relationship between a quantum of energy and the frequency of radiation is

Quantum of Energy = hv

The photoelectric effect is

The emission of electrons from a metal when light shines on the metal

the significance of the photoelectric effect and the line-emission spectrum of hydrogen to the development of the atomic model

The photoelectric effect shows the emission of an electron from a metal when the light is shined on it. The 4 different lights that appeared when a light was shown through a prism is part of the line, which is the emission spectrum.

How are wavelength and frequency of electromagnetic radiation related?

Wavelength and frequency are mathematically related

How is hydrogen's emission spectrum produced?

While in a given orbit, the electron is neither gaining nor losing energy. It can, however, move to a higher-energy orbit by gaining an amount of energy equal to the difference in energy between the higher energy orbit and the initial lower-energy orbit. When a hydrogen atom is in an excited state, its electron is in one of the higher-energy orbits. When the electron falls to a lower energy level, a photon is emitted, and the process is called emission. The photon's energy is equal to the energy difference between the initial higher energy level and the final lower energy level. Energy must be added to an atom in order to move an electron from a lower energy level to a higher energy level. This process is called absorption. The energy of each absorbed or emitted photon corresponds to a par ticular frequency of emitted radiation, Ephoton = hν.

Particles that carry a quantum of energy is called

a proton

hydrogen's line-emission spectrum

a series of specific frequencies of emitted electromagnetic radiation

Higher energy light has

a shorter wavelength than lower-energy light

There are many possible excited states that each have

a unique energy

an electron in an atom can move from one main energy level to a higher main energy level only by

absorbing an amount of energy exactly equal to the difference between the two levels

Energy must be added to an atom in order to move an electron from a lower energy level to a higher energy level. This process is called

absorption

An electron can move to a higher-energy orbit by gaining an

amount of energy equal to the difference in energy between the higher energy orbit and the initial lower-energy orbit

The energy of the electron is higher when it is in orbits that

are successively farther from the nucleus

In the equation c = λν,

c is the speed of light (in m/s), λ is the wavelength of the electromagnetic wave (in m), and ν is the frequency of the electromagnetic wave (in s-1).

In the equation c=λv,

c is the speed of light, λ is the wavelength of the electromagnetic wave, and v is the frequency of the electromagnetic wave. Because c is the same for all electromagnetic radiation, the product λv is a constant

Because c is the same for all electromagnetic radiation, the product λν is a

constant

When the electron is in one of these orbits, the atom has a

definite, fixed energy

Wavelength (λ) is the

distance between corresponding point on adjacent waves

the unit for wavelength is a

distance unit

In the early twentieth century, light was determined to have a

dual wave-particle nature

In 1905, Einstein expanded Planck's theory by introducing the radical idea that

electromagnetic radiation has a dual wave-particle nature

According to the Bohr model of the atom, which particles are allowed to exist in any one of a number of energy levels?

electrons

Quantum theory states that

electrons can exist in atoms only at specific energy levels

The process of an atom releasing energy when it moves to a lower energy state is called

emission

When an electron falls to a lower energy level, a photon is emitted, and the process is called

emission

When an electron falls to a lower energy level, a photon is

emitted, and the process is called emission

The photonś energy equals the

energy difference between two sublevels

in order for an electron in an atom to change from the ground state to an excited state,

energy must be absorbed

Electromagnetic radiation is a form of

energy that exhibits wavelike behavior as it travels through space

frequency and wavelength are mathematically

equal to each other: c=λv

hydrogen atoms can be

excited by whatever amount of energy was added to it

a state in which an atom has a higher potential energy than it has in its ground state is an

excited state

the energy of a photon is directly related to its

frequency

While in a given orbit, the electron is neither

gaining nor losing energy

The lowest energy state of an atom is its

ground state

the lowest energy state of an atom is its

ground state

Planck's Constant

h = 6.626 x 10^-34

The lower the frequency the ______ the wavelength.

higher

When a hydrogen atom is in an excited state, its electron is in one of the

higher-energy orbits

When a narrow beam of the emitted light was shined through a prism, it was separated into four specific colors of the visible spectrum. The four bands of light were part of what is known as the

hydrogen's emission-line spectrum

Niels Bohr proposed an idea that a

hydrogen-atom model that linked the atom's electron to photon emission

According to the Bohr model of the atom, electrons circle the nucleus

in specific, allowed orbits

in the bohr model of the atom, which orbit is an electron in its lowest energy state?

in the orbit closest to the nucleus

When a current is passed through a gas at low pressure, the potential energy of the gas atoms

increases

When an excited atom returns to its ground state,

it gives off the energy it gained in the form of electromagnetic radiation

Because air is mostly empty space, the value of 3.00 × 10^8 m/s is also

light's approximate speed through air

Because air is mostly empty space, the value of 3.00*10^8 meters per second is also

light's approximate speed through air

the higher the frequency, the ___ the wavelength

lower

depending on the type of electromagnetic radiation, it may be expressed in

meters, centimeters, or nanometers

a form of energy that exhibits wave behavior as it travels through space is

microwave radiation, ultraviolet radiation, and infrared radiation

A quantum of energy is the

minimum quantity of energy that can be lost or gained by an atom

The energy of the electron is higher when the electron is in orbits that are successively farther from the

nucleus

Quantum theory was developed to explain

observations such as the photoelectric effect and the line-emission spectrum of hydrogen

Bohr's model correctly the spectra of atoms with _________ electron(s)

one

The electron can circle the nucleus only in allowed paths, or

orbits

he energy of the electron is higher when it is in

orbits that are successively farther from the nucleus

a particle of electromagnetic radiation having zero mass and carrying a quantum of energy is called a

photon

When an electron moves from one main energy level to a main energy level of lower energy, a

photon is emitted

When light exhibits many wavelike properties, but it can also be thought of as a stream of particles. Each particle carries a quantum of energy. These particles are called

photons

Each particle carries a

quantum of energy

List the colors of light in the visible spectrum in order of increasing frequency.

red, orange, yellow, green, blue, indigo, violet

Because excited hydrogen atoms always produce the same line-emission spectrum, scientists concluded that hydrogen

releases energy of only certain values

The significant feature of wave motion is its

repetitive nature, which can be characterized by the measurable properties of wavelength and frequency

It was soon recognized, how ever, that Bohr's approach did not explain the

spectra of atoms with more than one electron nor the chemical behavior or atoms

Bohr's model of the hydrogen atom explained observed

spectral lines so well that many scientists concluded that the model could be applied to all atoms

In the equation, Quantum of Energy = hv,

the Quantum of Energy is in joules, v is the frequency, and h is a fundamental physical constant now known as Planck's constant; h = 6.626*10^-34

diffraction

the bending of a wave as it passes by the edge of an object or through a small opening

continuous spectrum

the emission of a continuous range of frequencies of electromagnetic radiation

The energy of a particular photon depends on

the frequency of the radiation

Explain the mathematical relationship among the frequency and wavelength of electromagnetic radiation

the mathematical relationship between frequency and wavelength is written as c = λν

Quantum of Energy

the minimum quantity of energy that can be lost or gained by an atom

Frequency (v) is defined as

the number of waves that pass a given point in a specific time, usually one second

What two experiments involving light and matter could not be explained by the wave theory of light

the photoelectric effect experiment and the hydrogen emission line spectrum experiment

Bohr's model did not explain

the spectra of atoms with more than one electron or the chemical behavior of atoms

in the equation c = λv, c represents

the speed of light

Because c=λv, we know that

v=c/λ

what color of light in the visible spectrum has the highest frequency?

violet

properties of light

wavelength and frequency

Light exhibits many

wavelike properties, but it can also be thought of as a stream of particles

Many of lights properties can be described in terms of

waves

Frequency is expressed in

waves/second

Process of emission

when an electron falls to a lower energy level

process of absorption

when energy must be added to an atom in order to move an electron from a lower energy level to a higher energy level

dual wave-particle nature of light

when light exhibits many wavelike properties, but it can also be thought of as a stream of particles. Each particle carries a quantum of energy

Orbits

when the electron can circle the nucleus only in allowed paths

interference

when waves overlap

5 examples of electromagnetic radiation

x rays, ultraviolet rays, infrared light, microwaves, radiowaves

Other kinds of electromagnetic radiation includes

x-rays, ultraviolet & infrared light, microwaves, and radio waves


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