Atomic Theory Flashcards
Who is accredited with thinking up the law of conservation of mass?
Antoine Lavoisier
This law says that “different pure samples of the same compound always contain the same proportions of each element of mass”
The law of definite proportions
What were John Dalton’s four postulates?
1) Each element is composed of tiny particles called atoms
2) All atoms of a given element are identical and all atoms of different elements are different
3) Atoms are not created or destroyed in chemical reactions. They are dissociated, combined, or recombined
4) Compounds are formed when atoms of different elements combine with one another. A given compound always contains the same relative numbers and types of atoms
Who discovered electrons?
J.J Thompson
Who discovered a nucleus with protons in atoms?
Earnest B Rutherford
equal to the number of protons plus the number of neutrons
Mass number
The number of protons (or electrons in a neutral atom)
Atomic number
Same element with a different number of neutrons
Isotope
Isotopes of an element exhibit _________ chemical behavior
Identical
Atomic mass given in the periodic table is an _________ of all of the isotopes of that element
Average
In mass spectrometry, less deflection means a ___________ mass
Larger
What is the equation for average atomic mass?
(Mass# x %)+(Mass# x %) = average mass
What is the equation for mass percent of an element in a substance?
Mass % of element= (# of atoms of element)(elements atomic mass) / (formula weight of compound) x 100
Linear distance covered before a wave starts to repeat itself
Wavelength
A low frequency wave has a __________ wavelength
Higher
What is the formula for wavelength in its relation to frequency?
C=(wavelength)(v)
What is the constant in the formula?
3 x 10^8 m/s
Who hypotheses that the energy radiated from a heated objects is emitted in discrete units or quants
Max Planck
Plancks constant is represented as ____
H
The higher the frequency the _________ the energy
Higher
Highly intense _____________ light does not eject any electrons
Low frequency
When the __________________ is reached electrons are ejected immediately
Threshold frequency
Increasing the intensity of the light at a frequency that will cause electrons to eject results in a ____________ however all electrons share the same velocity
Higher ejection rate
Increasing the frequency of the light increases the velocity of the ejected electrons, however all ejected electrons ___________________
Share the same velocity
A beam of light is a stream if particles called _________
Photons
What is Plancks equation?
E=hv
State Coulomb’s law
The force of attraction decreases as the distance between the outermost electron and the protons increase
The electrons that are furthest from the nucleus are partly _________ by the inner core electrons
Shielded
The minimum amount of energy that is required to remove the outermost electron form an atom in its gas phase
First ionization energy
Ionization energy generally __________ as you move across the periodic table
Increases
Electrons contained in the inner shell
Inner core electrons
Electrons contained in the outer shell
Valence electrons
N=1 can hold how many subshells?
1
What is the subshell n=1 can hold?
1s
What subshells does n=2 contain?
2s and 2p
How many electrons can subshell 2s hold?
2
How many electrons can subshell 2p hold?
6
How many electrons can 3s hold?
2
How many electrons can 3p hold?
6
How many electrons can subshell 3d hold?
10
The shielding effect ___________ for each subshell that is added
Increases
Electrons furthest from the nucleus have _________ potential energy
Higher
According to the QM model, all electrons under the same subshell have __________ energy
The same
A graphic representation of the space that and electron will occupy 90% of the time
Orbital
Electrons are added to the _______ energy orbitals available
Lowest
Atoms with unpaired electrons
Paramagnetic
atoms with no unpaired electrons
Diamagnetic atoms
The effective nuclear charge (the charge experience by an electron) is written as _______
Zeff
As you go across the periodic table the atomic radius __________
Decreases
Metals lose elections to form ________
Cations
Non-metals fain electrons to form _________
Anions
___________ share the same electronic configurations but have different radii
Isolectronic species
_________ are smaller than smaller than neutral atoms
Cations
________ are larger than neutral atoms
Anions
It’s harder to pull electrons from a ________ subshell
Full
First ionization energy generally _________ as atomic radii decrease
Increase
The second ionization potential for an atoms is always __________
Greater
An elements ability to attract electrons in a chemical bond
Electronegativity
Electrons will spend _______ time around the more electronegative element in a chemical bond
More
Electronegativity generally __________ as you move across the periodic table
Increases
Electronegativity ________ as atomic radius decreases
Increases
Who was the first to think about atomic theory?
Democritus
