Ch 5 Electrons in Atoms

5.1 Light and Quantized EnergyReview Vocabulary________________ the rays and particles —alpha particles, beta particles, and gamma rays—that are emitted by radioactive materialNew Vocabularyelectromagnetic radiationwavelengthfrequencyamplitudeelectromagnetic spectrum

Main Idea Light, a form of electronic radiation, has characteristics of both a____________ and a _______________

5.1 THE ATOM AND UNANSWERED QUESTIONS Recall that in Rutherford's model, the atom’s mass is concentrated in the nucleus and electrons

move around it. Atom is mostly ____________ space The model does not explain:

o _________the electrons were arranged around the nucleus.o _________negatively charged electrons aren’t pulled into the positively charged nucleus.o the_______________ properties of the elements

a better description of the __________________ was needed In the early 1900s, scientists observed certain elements _____________________________ when

heated in a flame. Analysis of the emitted light revealed that an element’s chemical ________________ is related to

the _______________________ of the __________________in its atoms.

5.1 THE WAVE NATURE OF LIGHT Visible light is a type of _______________________________, a form of energy that exhibits wave-

like behavior as it travels through space. All waves can be described by ____________characteristics.

1) The ___________________ is the wave’s height from the origin to a crest.

2) The ______________________ (λ) is the shortest distance between equivalent points on a continuous wave.

3) The ___________________(f) is the number of waves that pass a given point per second. Frequency is measured in units of Hertz (Hz). 1 Hz = ___________

Wavelength and Frequency are __________________related, so as one goes _____ the other goes ____________.

quantumPlanck's constantphotoelectric effectphotonatomic emission spectrum

The product of the wavelength and the frequency of any electromagnetic wave is he speed of light (3.00 108 m/s).

o The wave speed equation is _____________.o C = ___________________o λ = ___________________o f = ___________________

Different __________________ of light are different _______________ of light. This also means that each color has a certain wavelength. The whole range of frequencies and wavelengths is called the ________________________. Sunlight contains a ________________________ of wavelengths and frequencies. A_________________ separates sunlight into a continuous spectrum of colors. The electromagnetic spectrum includes _________ forms of electromagnetic radiation.

Example CalculationCalculate the wavelength of yellow light emitted by a sodium light if the frequency is 5.10 x 1014 Hz.

5.1 the particle nature of light The wave model of light cannot explain all of light’s characteristics.

o It does not explain all of light’s interactions with matter.o Why do heated objects emit only certain frequencies of light?o Why do some metals emit electrons when colored light of a specific frequency shines on

them? In 1900, the German physicist ____________________ began searching for an explanation as he

studied the light emitted from heated objects and made the following conclusions.o Matter can gain or lose _____________ only in small, specific amounts called

_______________.o A ____________ is the ________________ amount of energy that can be gained or lost by

an atom.o Planck’s constant has a value of ________________________.

The ____________________________ is when electrons are emitted from a metal’s surface when light of a certain frequency shines on it.

Long Wavelength

=Low Frequency

=Low ENERGY

Short Wavelength

=High Frequency

=High ENERGY

o The wave model of light could not explain this either.

_____________________________ proposed in 1905 that light has a _____________________. A beam of light has wavelike and particlelike properties. A ______________ is a ________________of electromagnetic radiation with ______________ that

carries a __________________ of energy. Ephoton = hf

Ephoton represents energy. h is Planck's constant. f represents frequency.

Atomic Spectra ____________ light is made up of_________ the colors of the ________________spectrum. Passing it through a prism _________________ it. Each________________ gives off its own characteristic colors. Can be used to __________________ the atom. This is how we know what ______________are made of.

The atomic emission spectrum of an element is the __________________________ of the electromagnetic waves emitted by the atoms of the element.

Each element’s atomic emission spectrum is unique. Light in a neon sign is produced when electricity is passed through a tube filled with neon gas and

excites the neon atoms. The excited atoms ___________________ to _________________________.

The Math in Chapter 5 There are 2 equations:

c =

• These are called the _________________________

• Unique to each element, like___________________!

• Very useful for_________________ elements

E = h ________________!

Examples What is the wavelength of blue light with a frequency of 8.3 x 1015 hz?

What is the frequency of red light with a wavelength of 4.2 x 10 -5 m?

What is the energy of a photon of each of the above?

5.2 Quantum Theory and the AtomReview Vocabulary

atom: the smallest particle of an element that retains all the properties of that element, is composed of electrons, protons, and neutronsNew Vocabulary

ground state Main Idea - quantum numberde Broglie equationHeisenberg uncertainty principlequantum mechanical model of the atom

Bohr’s model of the atom (Planetary Model) Why do elements’ atomic emission spectra show only certain frequencies? In 1913 ________________, a Danish physicist, was working in Rutherford’s lab and proposed a

_______________________ for the hydrogen atom that seemed to answer this question.

Bohr’s model correctly predicted the frequency lines in hydrogen’s atomic emission spectrum. The lowest allowable energy state of an atom is called its _______________________. When an atom gains energy, it is in an _______________________. Bohr suggested that an electron moves around the nucleus only in certain allowed circular orbits.

BUT, Why don’t the electrons fall into the nucleus?o Move like planets around the sun.o In specific concentric circular paths, or orbits, at different levels.o A ____________ (amount) of fixed energy separates one level from another.o Electrons can _______________from one level to another

Each____________ was given a number, called the ___________________.

An _____________________ of an electron is analogous to the rungs of a laddero The electron_________________ exist between energy levels, just like you can’t stand

between rungs on a laddero A____________________ of energy is the amount of energy required to move an electron

from one energy level to another

atomic orbitalprincipal quantum numberprincipal energy levelenergy sublevel

Hydrogen’s single electron is in the n = 1 orbit in the ground state.o When ___________________________, the electron moves to a higher energy state such

as the n = 2 orbit or n = 5 orbit.o _________________________________ can move the electron up to different energy

levels. The electron is now said to be ___________________.o As the electron falls back to the ground state, it gives the energy back as _____________.

Bohr’s model explained the hydrogen’s spectral lines, but _____________ to explain any other element’s lines.

The behavior of electrons is still not fully understood, but it is known they do not move around the nucleus in circular orbits.

The Quantum Mechanical Model

_________________ __________________explains how very small particles behave Quantum mechanics is an explanation for_____________________ particles and atoms as waves _____________________________ describes the motions of bodies much larger than atoms

In 1924 _______________________, a French graduate student in physics, proposed an idea that eventually accounted for the fixed energy levels of Bohr’s model.

o _____________ is still _________________ in his model. It comes in chunks.o Louis de Broglie (1892–1987) hypothesized that particles, including electrons, could also

have wavelike behaviors. The de Broglie equation predicts that all moving particles have wave characteristics.

represents wavelengths h is Planck's constant. m represents mass of the particle. f represents frequency.

The figure illustrates that electrons orbit the nucleus only in whole-number wavelengths.

___________________________, a German theoretical physicist and a contemporary of de Broglie proposed an idea that had profound implications on atomic theory.

o Heisenberg showed it is impossible to take any measurement of an object without disturbing it.

It is more obvious with the very small objects To measure where a electron is, we use light. But the light energy moves the electron And hitting the electron changes the frequency of the light.

o The ___________________________________________states that it is fundamentally impossible to know precisely both the velocity and position of a particle at the same time.

o The only quantity that can be known is the probability for an electron to occupy a certain region around the nucleus.

In 1926, Austrian physicist _____________________________ furthered the wave-particle duality theory proposed by de Broglie.

o Schrödinger treated electrons as waves in a model called the _________________________________________________ of the atom.

o Schrödinger’s equation applied equally well to elements other than hydrogen.o The quantum mechanical model is a mathematical solutiono It is not like anything you can see (like plum pudding!)o The atom is found inside a blurry “electron ___________”o Schrödinger’s wave function predicts a three-dimensional region around the nucleus called

the _____________________.

Atomic orbitals The Quantum Mechanical Model:

o Has energy levels for electrons.o Orbits are not circular.o It can only tell us the probability of finding an electron a certain distance from the nucleus.

Principal quantum number (n) indicates the relative size and energy of atomic orbitals. n specifies the atom’s major energy levels, called the principal energy levels. ______________________ are contained within the principal energy levels like theater seats

arranged in sections: letters s, p, d, and f _________________ number of electrons that can fit in an energy level is ________.

Each energy _________________ relates to orbitals of ________________________.

Orbital Shapeso s - sphericalo p - dumbbello d – cloverleafo f - just wild

5.3 Electron ConfigurationReview Vocablulary

electron: a negatively charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleusNew Vocabulary

electron configurationaufbau principlePauli exclusion principleHund's rulevalence electronselectron-dot structure

Main Idea - A set of __________________ determines the arrangement in an atom.

5.3 ground state electron configuration The arrangement of electrons in the atom is called the ____________________________________. The _________________________ states that each electron occupies the lowest energy orbital

available.

The ________________________________________ states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins.

__________________________ states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same energy level orbitals.

o When electrons occupy orbitals of _________energy, they don’t __________ up until they have to.

_______________________________ uses noble gas symbols in brackets to shorten inner electron configurations of other elements.

Orbital Diagrams Shows the ___________ associated with a particular electron Shows the _________________ of electrons in an atom Explains bonding and various properties Can be called an ________________________

– Aufbau is German for “building up”

Let’s write the orbital diagram for _______________ We need to account for all ____ electrons in phosphorus The first two electrons go into the ____ orbital Notice the _______________direction of the spins

o only 13 more to go... The next electrons go into the ____ orbital

o only 11 more... The next electrons go into the ____ orbital

o only 5 more... The next electrons go into the ____ orbital

o only 3 more... The last three electrons go into the ____ orbitals.

o They each go into separate shapes (Hund’s)o 3 unpaired electrons

Electron configuration = ______________________

Example Electron configurations

Calcium ___________________ Chromium ____________________

Orbitals fill in an order ______________ energy to higher energy. Adding electrons can change the energy of the orbital. ________orbitals are the most__________. However, ________________ orbitals have a lower energy, and are next best

o Makes them more stable.o Changes the filling order

The electron configurations (for chromium, copper, and several other elements) reflect the increased stability of half-filled and filled sets of s and d orbitals.

____________________________ are defined as electrons in the atom’s outermost orbitals—those associated with the atom’s highest principal energy level.

_____________________________ consists of the element’s symbol representing the nucleus, surrounded by dots representing the element’s valence electrons.