Chemistry Ch 5 - History of Atoms
Studied by 126 people
Learn
Practice Test
Spaced Repetition
Match
Flashcards1/119
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
120 Terms
What are atoms composed of?
Protons, Neutrons, Electrons
Who discovered Protons
Eugene Goldstein
Who discovered Neutrons?
James Chadwick
Who discovered Electrons
J.J. Thomson
What is the difference between Relative and Actual Mass
Relative mass is comparing against something else, such as Atomic Mass Units which are compared to Carbon-12. Actual is weight in a standard unit of measure, such as grams.
What is the relative mass of a Proton
1 AMU
What is the actual mass of a Proton?
1.673×10-24 g
What is the Relative Mass of a Neutron?
1 AMU
What is the Actual Mass of a Neutron
1.675×10-24 g
What is the Relative Mass of an Electron
1/1837 AMU
What is the Actual Mass of an Electron
9.110×10-28 g
What does AMU stand for?
Atomic Mass Unit
What are all the names for the current model of the atom?
Charge Cloud Model
Orbital Model
Wake Mechanical Model
Quantum Mechanical Model
Who discovered the Charge Cloud Model?
Erwin Schrödinger
What is the difference between continuous and discontinuous ideas of matter?
If you were to cut matter in half with an infinitely sharp knife, then in a continuous theory of matter, you could keep going forever, but in a discontinuous theory there will be a point where you will not be able to divide any further.
Who supported the continuous theory of matter?
Aristotle
Who supported the discontinuous theory of matter?
Democritus and Leucippus
Did continuous theory of matter or discontinuous theory of matter prevail after the Greeks?
Continuous
Who created the first modern theory of the atom?
John Dalton
Who created the first model of the atom?
John Dalton
Did Dalton’s model have electrons, protons, neutrons, or a nucleus?
No to all of them.
What are the 6 statements of Dalton’s Atomic Theory?
Elements are composed of minute, indivisible particles called atoms
Atoms of the same element are alike in mass and size
Atoms of different elements have different masses and size
Chemical compounds are formed by the union of two or more atoms of different elements
Atoms combine to form compounds in simple numerical rations
Atoms of two or more elements may combine in different rations to form different compounds
What laws did Dalton derive his theory from?
Law of Conservation of Mass
Law of Multiple Proportions
Law of Constant Compositions
Who was working with vacuum tubes?
William Crookes
What did Crookes tubes eventually become?
TVs
What is in a cathode ray tube?
Beams of electrons fired from a cathode
What is the charge of a cathode?
The charge of a cathode is negative.
What is the charge of an anode?
The charge of an anode is positive.
Who said the beams of the cathode ray tubes were made of particles?
J.J. Thomson
Who discovered/coined the term corpuscles?
J.J. Thomson
What were corpuscles really?
Electrons
How did JJ Thomson arrange the corpuscles in his atom?
Said they were floating around a sea of positive charge.
What model did Thomson create?
The plum pudding model
What ratio about electrons did JJ Thomson discover?
Their charge to mass ratio.
Which of the following did the Plum Pudding model have: electrons, protons, neutrons, or a nucleus?
Electrons
Who conducted the oil drop experiment?
Robert Millikan
Who found the charge of an electron
Robert Millikan
How did Millikan find the charge of an electron?
Millikan's oil drop experiment: Suspended oil droplets in an electric field and measured their motion. By adjusting the field strength, he could balance the gravitational force acting on the droplets. Using this, he determined the charge of an electron to be 1.6 x 10^-19 coulombs.
He then used Thomson’s charge to mass ratio to find the mass of the electron.
What is the charge of an electron?
1.6×10-19 coulombs
Who conducted the Alpha Particle Gold Foil Scattering Experiment?
Ernest Rutherford
What famous experiment did Ernest Rutherford conduct?
The Gold Foil Experiment
What famous experiment did Robert Millikan conduct?
The Oil Drop Experiment
What occured in Ernest Rutherford’s Gold Foil Experiment?
Alpha particles were shot at a thin gold foil. Most passed through, but some were deflected. This led to the discovery of the atomic nucleus and the concept of a mostly empty atom.
What was the smallest angle of deflection in the Gold Foil Experiment?
5°
What was Ernest Rutherford’s model of the atom?
The nuclear model
Which of the following did the nuclear model have: electrons, protons, neutrons, or a nucleus?
Electrons, nucleus
What was the problem with the nuclear model?
The electrons would fall towards the positively charged nucleus, causing the atom to blink out.
How was the problem to the nuclear model solved?
Neils Bohr introducted Quantum Mechanics
Why is quantum mechanics called such?
Because it is based of off a quantum of energy
How did quantum mechanics solve the nuclear model?
It stated that at every quantum of energy, electrons could exist as standing waves, so did not fall into the nucleus.
Who created the planetary model?
Neils Bohr
What model did Bohr create?
The planetary model
What is the Pauli Exclusion Principle?
No two electrons can have the same set of Quantum Numbers
What are quantum numbers?
Basically the address of every electron.
What is the Heisenburg Uncertainty Principle?
The Heisenberg Uncertainty Principle states that it is impossible to simultaneously know the exact position and momentum of a particle with complete accuracy.
Along with that, the accuracy of one inversely affects the accuracy of the other. So if you knew the velocity of a particle with 100% accuracy, you would know its position with 0% accuracy.
Are electrons waves or particles?
Trick question, they are both! Particle-wave duality is a thing. If you are confused, welcome to quantum mechanics. Everything is confusing.
What is the Ground State of an electron?
The lowest possible energy level at which an electron can exist.
Is the ground state stable?
Yes!
What is the Excited State of an electron?
An electron at a higher state than the ground state.
Is the excited state stable?
No!
How does an electron get to an excited state?
It “Quantum Jumps“.
What happens in a quantum jump?
Energy is put into an electron/atom, and when the amount of energy reaches at least 1 quantum, the electron will jump a number of energy levels equivalent to the number of quantums of energy put into it.
How does an electron return to the ground state?
It releases the energy it absorbed to enter the excited state as light.
What are the levels of organization in Schrodinger’s Model?
Electron Cloud ← Energy Levels ←Sublevels←Orbitals
How many electrons can an obrital hold?
2
What is radioactivity?
Spontaneous emission of particles and/or rays from the nucleus of an atom.
Who discovered ratioactivity?
Henri Bequerel
Who discovered X-Rays?
Wilhelm Roentgen
What are the three types of radiation?
Alpha Particles, Beta Particles, Gamma Rays
What is the symbol for Alpha Particles?
α
What is the symbol for Beta Particles?
β
What is the symbol for Gamma Rays?
γ
What is an alpha particle?
He+2, which is basically a helium nucleus, or 2 p & 2 n
How does an alpha particle affect A?
Decrease of 4
How does an alpha particle affect Z?
Loss of 2
What stops an alpha particle?
A piece of paper.
What is the speed of an alpha particle?
<10% the speed of light
What does A stand for?
Mass number.
What does Z stand for?
Atomic number
What is a beta particle?
An electron
Where does a beta particle come from?
The decomposition of a neutron
What is the decomposition of a neutron called when it produces a beta particle?
Beta decay
What does decomposition of a neutron yield?
A beta particle and a proton
How does beta decay affect A?
No change
How does beta decay affect Z?
Increase of 1
What stops beta particles?
A thin sheet of Al
What is the speed of beta particles?
<90% the speed of light
What is a Gamma Ray?
High speed light
What is the mass/charge of a gamma ray?
None measurable
What is the Gamma Ray’s impact on A?
No impact
What is the Gamma Ray’s impact on Z?
No impact
What can stop a Gamma Ray?
Lead
Why are you asked to wear lead during an X-Ray?
To protect your body from excess radiation, especially your reproductive parts.
What is the speed of a gamma ray?
The speed of light (3.00×108 m/s)
What is Atomic Number?
Number of Protons
What is Mass Number?
Sum of protons+neutrons, always whole
What is Atomic Mass
Weighted average mass numbers of all isotopes compared to Carbon 12
What ion do Alkalines make?
+1
What ion do Alkaline Earth Metals make?
+2
What ion do Transition Metals make?
Variable 😭