Chemistry Exam 2 Flashcards
What is light?
light is a wide range of energy projected by many different sources
What is wavelength?
distance between peaks
What is frequency?
cycles per second
What does speed of light equal?
speed of light= wavelength x frequency
c=(lambda)(v)
What is frequency directly proportional to?
energy
Is the wavelength shorter or longer when the frequency is high?
shorter
(the the higher the frequency, the shorter the wavelength and the higher the energy.)
As energy increases what happens to the frequency?
The frequency increases
What did Einstein observe?
He observed that when light is shined on a metal surface, electrons are produced from the surface, and the electrons emitted from the metal surface are photoelectrons. This phenomenon is called the photoelectric effect
What is Planck’s equation?
E=hv
(energy= frequency x planck’s constant)
Does an infrared light or ultraviolet light have more energy?
Ultraviolet because it is at a higher frequency, therefor higher energy.
How are photons created?
When an electron in an excited state jumps to a higher shell, and when it eventually falls back to its original shell it emits a photon
The further the photon falls_____?
the higher energy the photon will be
What does the Bohr model explain?
The Bohr model explains that electrons orbit the nucleus at fixed energy levels. Orbits further from the nucleus exist at higher energy levels. When electrons return to a lower energy level, they emit energy in the form of light known as photons.
Light is ___ as electron falls back to a lower energy level
emitted
Electron ___ energy and is excited to unstable energy level.
absorbs
What do electrons exist as?
both particles and waves (like photons)
What are orbitals described by?
4 quantum numbers
How many electrons can an orbital have?
2
Can there be multiple orbitals?
yes
what letter represents the principal quantum number?
n
What is the range for n?
1,2,3…
What does the principal quantum number represent?
the electron shell (distance form the nucleus)
What letter represents the angular quantum number?
l
What is the range for l?
l=0,….(n-1)
What letter represents the magnetic quantum number ?
m1
What is the range for m1?
m1= -l,…,0,…,l
What does the angular quantum number (l) govern?
the subshells
What are the letters used for the subshells?
s,p,d,f
when l=0, what can ml only be?
0
What is the quantum number for electron spin?
ms (+1/2 & -1/2)
What happens when electrons of the same charge are spinning in opposite directions?
they won’t repel each other’s negative charge
What shape does the s orbital have?
a spherical shape
what does l equal in the s orbital?
0
what shape do the p orbitals have?
p orbitals have a dumbell/egg shape
What are the values for ml in the p orbital?
ml= -1,0,1
What does l equal in the p orbital?
1
What shape does the d orbital have?
a clover shape
What are the values for ml in the d orbital?
ml= 1, 0, 2, -1, -2
What does l equal in the d orbital?
2
What shape does the f orbital have?
there is no distinct shape
What are the value for ml in the f orbital?
ml= -3, -2, -1, 0, 1, 2, 3,
what does l equal in the f orbital?
3
What elements are alkaline metals?
Group 1: Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs), Francium (Fr)
What elements are Alkaline earth metals?
Group 2: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), Radium (Ra)
what elements are Halogens?
Group 7: Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (As)
What elements are Noble Gases?
Group 8: Helium (He), Neon (Ne)m Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)
Are Groups on the periodic table left to right, or up and down?
Up and Down
Are Periods on the periodic table left to right or up and down?
Left to right
What is the reactivity trend on the periodic table?
Reactivity increases as you go down the column
Groups on the periodic table have similar chemical properties true or false?
True
Where do electrons exist?
in orbitals
What are the two rules to the Pauli Exclusion Principle?
- No two electrons in an atom may have the same set of four quantum numbers
- No orbital may have more than two electrons and they must have opposite spins
Aufbau’s Principle rule 2
Orbitals are filled in order of incresing energy
Where will electrons always go?
to the lowest energy state
When is Aufbaus’s principle violated?
If the electron is given energy; because this will cause the electron to jump to a higher energy state
Write out the electron configuration for Ga
1s^2, 2s^2, 3s^2, 3p^6, 4s^2, 3d^10,4p^1
Hund’s Rule
For electrons with degenerate orbitals, the lowest energy is attained when the number of electrons having the same spin is maximized
What do we use to do a condensed electron configuration?
The noble gas in the period above
What is Zeff?
Z effective is how much positive charge an electron “sees” based on number of electrons between
How do you calculate the effective nuclear charge
Zeff= (number of protons [atomic #]- (the number of core electrons [row it’s in])
Example: What is the effective nuclear charge for an electron in the n=2 in an atom of fluorine?
Zeff=9-2
Answer = 7
What are core electrons?
are all electrons in inner energy levels including completely filled d and f subshells
What is electron shielding?
the blocking of valance shell electrons attraction by the nucleus, due to the presence of inner-shell electrons (think of in-class college bar analogy)
Where does the Zeff trend increase?
As you move to the right on the periodic table
How is the size of an atom measured?
atomic radius
What is the atomic radius trend?
atomic radius increases as you move down & to the left of the periodic table
What is the largest element?
Francium
Cations
loses electrons, has a positive charge, shrinks because it’s losing electrons
Anions
gains electrons, negative charge, grows because it’s gaining electrons, larger than their parent atom
True or False: Cations are larger than their parent atom
False, cations are smaller due to losing electrons
True or False: Anions are larger than their parent atom
True
Arrange Mg^2+, Ca^2+, Ca in order of decreasing radius (largest to smallest)
Ca, Ca^2+, Mg^2+
What is the ionic radius trend?
As you move down a column on the periodic table the ionic radius increases
What is an isoelectronic series?
a group of atoms/ions that have the same number of electrons
What will transition metal cations do?
they will remove electrons from the s subshell before the d subshell because they have a partially filled d block
What is ionization energy?
It is the amount of energy required to remove an electron from an atom/ion in a gaseous state (energy needed to make a cation)
What is the increasing first ionization energy trend?
Up and to the right
What element has the highest first ionization energy?
helium
What is electron affinity?
The energy released when an electron is added to the gaseous state of an atom/ion (makes an anion)
What are most electron affinities?
negative (releasing)
What are all ionization energies?
positive (absorbing)
What is metallic character?
It is the measure of the degree to which an element exhibits the chemical and physical properties of a metal
what are some metallic characteristics?
lustrous, high melting point, and very conductive
What is the metallic trend?
Increases down and to the left
What element is the most metallic?
Francium
