Module 3 Test Flashcards
What 4 things did early philosophers believe matter was composed of?
Earth, water, air, and fire.
Why did Democritus’s ideas about matter go against other philosophers beliefs?
Because Democritus could not answer the question of “What holds the atoms together?”.
Why were Democritus’s ideas about matter widely rejected?
Aristotle rejected the notion of atoms because it went against his beliefs. Aristotle was very influential at this time so many continued to reject Democritus’s ideas as well.
What was the book A System of Chemical Philosophy published by John Dalton about?
Describes how Dalton revisited and revised Democritus’s ideas and worked to determine the mass ratios of the elements involved in the experiments Dalton conducted.
Who was John Dalton?
John Dalton was a schoolteacher in England that developed the modern atomic theory by reviving and revising Democritus’s ideas by his performed experiments.
Why do you think John Dalton is important in understanding atoms?
Because his modern atomic theory explains that the conservation of mass in chemical reactions is the result of the rearrangement of atoms during the reaction.
What is an atom?
An atom is the smallest particle of matter that retains the properties of the element.
How do we know atoms exist?
Many experiments have been conducted since Dalton’s time to prove that atoms exist.
What is a cathode ray tube for?
It is used to help researchers study the relationship between mass and charge.
What is an electron?
An electron is a negatively charged particle that is a part of all forms of matter.
Who is J.J. Thomson?
J.J. Thomson was the first to identify the first subatomic particle, the electron.
How did J.J. Thomson identify the electron?
He did this by determining the charge-to-mass ratio of the charged particle, then compared that ratio to other known ratios.
Which of Dalton’s theories did J.J. Thomson disprove?
Thomson disproved Dalton’s theories about atoms not being divisible. His discovered proved Dalton incorrect because atoms can be divided into smaller subatomic particles.
What did Ernest Rutherford prove?
Rutherford proved that Thomson’s plum pudding model was incorrect because it did not match the results of his Gold experiment.
What did Rutherford contribute to atomic theory?
His results from the gold experiment proved that an atom has a positive charge and mass contained in the center of the atom.
What did Rutherford discover?
He discovered that atoms have a nucleus and protons/
Who discovered the neutron?
James Chadwick
What are quarks?
The first experimental evidence for subatomic particles, subatomic particles that make up the composition of the structures for protons and neutrons
Who is Henry Moseley and what did he contribute to atomic theory?
He was an English scientist that discovered atomic number, which explains that the number of protons in an atom identifies it as an atom of a particular element.
What does periodicity have to do with how the periodic table is structured?
The periodic table is organized left-to-right and top-to-bottom by increasing atomic number. This pattern of order within the periodic table is called periodicity.
Where is the atomic number listed on an element on the periodic table?
The atomic number is listed to the left or on top of the element’s symbol on the periodic table.
Where is the atomic mass listed on an element on the periodic table?
The atomic mass is listed below the element’s chemical name at the bottom of each element on the periodic table.
What is an isotope?
An isotope is an atom with the same number of protons but different number of neutrons.
What is the law of definite proportions?
A chemical in a compound always contains the same elements in exactly the same proportions by weight or by mass.
What is the law of conservation of mass?
Mass cannot be created nor destroyed in chemical or physical changes.
What law does this prove?
NaCl= 39.34% of Na and 60.66% Cl 1:1 ratio of Na to Cl
The law of definite proportions
What law does this prove?
30 kg of wood + 1 kg of fire —> 28 kg of ashes + 3 kg of smoke
The law of conservation of mass
What is the law of multiple proportions?
When two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers
What law does this prove?
CO CO2
Mass of C 12g 12g
Mass of O 16g 32g
Ratio C:0 1:1 1:2The law of multiple proportions
What is a proton?
A subatomic particle that ha a positive charge and is found in the nucleus of an atom
What is a neutron?
A subatomic particle that has a neutral/ no electric charge and is found in the nucleus of an atom
What is an electron?
A subatomic particle that has a negative electric charge and is found in the electron cloud surrounding the nucleus
What did Democritus suggest?
Suggested “indivisible” pieces of matter called atomos (atoms)
What did Aristotle believe?
Believed that matter was composed of air, water, fire, and earth, this attacked Democritus’s ideas and halted the progress of the atom for over 2,000 years
What did Dalton do with Democritus’s beliefs?
Revised them and determined elements were made of one kind of atom and they could combine to form compounds
What did Dalton and Democritus agree on?
Atoms took the shape of solid spherical balls
What are some of Dalton’s atomic theory principles that are always true?
Atoms of different elements differ in their physical and chemical properties.
Atoms of different elements combine in simple, whole-number ratios to form compounds.
In chemical reactions, atoms are combined, separated, or rearranged but never created, destroyed, or changed.
In Thomson’s plum pudding model, what were the electrons?
The electrons were the negatively charged particles that “floated” through the pudding
In Thomson’s plum pudding model, what were the protons?
The protons were the positively charged pudding
What did Thomson discover?
Electrons
What did Thomson use to discover electrons?
The cathode ray tube
What did Rutherford discover?
Most of the atom is empty space with a nucleus in the center
What are the remaining principles of Dalton’s theory that were proved to be not always true?
All matter is composed of extremely small particles called atoms which cannot be subdivided, created, or destroyed.
Atoms of given elements differ in their physical and chemical properties.
Ernest Rutherford was a student of JJ Thomson. When he got his own lab, he took on 2 students: Hans Geiger and Ernest Marsden, along with one of Thomson’s students Niels Bohr. What was the name of their famous experiment?
Gold Foil Experiment
So in the plum pudding model of the atom, the “dough” was actually a ____ charged sea.
Positively
When they shoot alpha particles at the gold foil, where do most of them go?
Right through the foil as if nothing is there.
What would make the alpha particles bend away from the center?
They are deflected by other positively charged particles in the atom
What would make alpha particles bounce right back?
They hit a positively charged particle head on (like a billiard ball hitting another head on)
What is an alpha particle?
Positively charged radioactive particle
What were some problems with Rutherford’s model?
The model believed electrons orbit around the nucleus like planets around the sun.
Opposites attract, so the positively charged nucleus should attract the negatively charged electrons.
What was the main problems with Rutherford’s gold experiment?
He could not explain why the electrons do not crash into the nucleus.
Who tried to solve the question Rutherford could not answer?
Niels Bohr
How did Bohr try to solve Rutherford’s unsolvable question?
He proposed that electrons travel around the nucleus in specific energy levels that are each a certain distance from the nucleus
What did Bohr say that energy levels worked like?
Energy levels worked like rungs of a ladder
Why do energy levels work like rungs on a ladder?
You can only stand on the rungs, not in between the spaces.
In relation, electrons can only be in one energy level or another not in between.
What was the last subatomic particle to be discovered?
The neutron
Who discovered the neutron in 1932?
James Chadwick
True or False: Many of these scientists were laughed at and dismissed because they were not taken seriously.
True
What was the first thing Rutherford, Geiger, Marsden, and Bohr concluded from the gold foil experiment?
Most of the atom is empty space because alpha particles pass right through it.
What did they conclude about the atom?
The atom has a small positively charged nucleus
Is Rutherford’s model of the atom the final model that we use today?
Nope, our understanding of the atom continued to evolve (still to this day)
What are the two ideas Democritus made that were commonly acknowledged?
Everything in the universe if made of atomos.
Atoms are dense, indestructible spheres
What are the two events involved with Aristotle?
Everything was made of fire, water, earth, and air.
He halted the progress of the atom for over 2,000 years.
Who has been called the “Father of Modern Chemistry”?
Antoine-Laurent de Lavoisier which related to his emphasis on careful experimentation
What two important things did Lavoisier discover?
He discovered the law of conservation of mass and the element oxygen.
Who published the “Atomic Theory of Matter” stating all matter is made of atoms?
John Dalton
What are the common discoveries that Dalton made?
Atoms combine to form compounds.
All atoms of the same elements are alike.
What did Planck discover?
He discovered that atoms and molecules emit and absorb different levels of energy in the form of electromagnetic radiation.
What did Thomson propose?
He proposed that atoms have an overall + charge with - charged dispersed throughout.
Who used the Brownian Motion to prove that atoms exist?
Einstein
Who was known for his publication of “The Theory of Relativity”?
Einstein
What did Milikan discover?
He discovered the exact charge of an e (electron)
What experiment did Rutherford perform?
The Gold Foil Experiment
What did Rutherford discover from his experiment?
The nucleus is mostly empty space
Does the nucleus contain positive, neutral, or negative charged particle?
Positive charged particles
What did Bohr conclude?
E (electrons) are located in specific energy levels like rungs on a ladder
Who discovered the Quantum Mechanical Model to locate e (electrons)?
Schrodinger
What did Schrodinger discover about e (electrons)?
E (electrons) do not move in set paths, they move in waves with no exact location
Who proposed the Uncertainty Principle?
Heisenberg
What did Heisenberg propose?
He proposed that you can never know the exact position or speed of an e (electron)
What was the main discovery that Chadwick made?
The discovery of the neutron
What did DeBrogli propose?
He proposed that electrons act like waves in a confined space
What can these confined waves only have?
Confined waves can only have certain frequencies
What do these certain frequencies from confined waves relate to?
They relate to the energy of the wave
In atoms, what are the frequencies of the electrons related to?
The frequencies of electrons are related to the energy level the electron is found in
What does electromagnetic radiation travel in?
Electromagnetic radiation travels in waves
What do different types of electromagnetic radiation have?
They have different frequencies
What does light have the properties of?
Light has the properties of both waves and particles
What is the photoelectric effect?
It states certain frequencies of light cause electrons to be released when it strikes metal
What is the ground state?
The state where atoms normally exist with electrons at the lowest possible energy levels, closest to the nucleus
What is the excited state?
Electrons can gain energy and move to this state farther from the nucleus
Is the excited state stable or unstable?
Unstable
What does it mean that the excited state is unstable?
The electron will release energy and fall back to the ground state
What does the energy released from the excited state correspond to?
The energy released corresponds to the energy difference between different orbitals in the atom
When are different colors of light emitted?
Different colors of light are emitted at different energies
What is an emission spectra?
The light released when an electron falls from an excited state to a ground state which is unique to that element
What is the light released when an electron falls from an excited state to a ground state that is unique to that element?
Emission spectra
What does an electron emit a characteristic wavelength of light?
When dropping from a higher energy state to a lower energy state
What are electron orbitals?
Regions of high probability of finding electrons
What do electron orbitals do?
They show where electrons are
Different orbitals have different what?
They have different shapes and orientations
What are the names of the electron orbitals?
S, p, d, and f orbitals
How many orbitals does the s-orbital have?
1 orbital
How many electrons can the s-orbital hold max?
2 electrons max
What is the shape of the s-orbital?
Spherical shape
How many orbitals does the p-orbital have?
3 orbitals
How many electrons can the p-orbital hold max?
6 electrons max
What is the shape of the p-orbital?
Dumbbell shape
How many orbitals does the d-orbital have?
5 orbitals
How many electrons can the d-orbital hold max?
10 electrons max
What is the shape of the d-orbital?
Clover leaf shape with 1 donut shape orbital
How many orbitals does the f-orbital have?
7 orbitals
How many electrons can the f-orbital hold max?
14 electrons max
What is the shape of the f-orbital?
Tetrahedral
What does writing electron configurations do?
Show us where each electron is located
What is the Pauli Exclusion Principle?
Only 2 electrons can be in the same orbital at a time
What is the Aufbau Principle?
Electrons fill orbitals with the lowest energy first
What is the Hund’s Rule?
Electrons will fill all the orbitals with the same energy level (n) and quantum numbers (l) singly before pairing begins
What do orbital diagrams help us show?
They help us show how electrons fill orbitals
What is long-hand notation?
Long-hand notation shows each orbital with the number of electrons that are in it as a superscript.
What is short-hand notation?
Starts with the last noble gas prior to the atom you are writing then, adds only the electrons in orbitals that the noble gas does not have
What is shorthand notation used for?
Shorthand notation is used for larger atoms.
What is the present day model of the atom called?
Quantum model
Why were electrons assigned 4 quantum numbers when dealing with the quantum model?
To define where it is located
When using quantum numbers, what are we talking about most oftenly?
We are most often talking about the very last electron in the electron cloud.
What is the first quantum number called?
The principal quantum number (n)
What does the quantum number (n) correspond to?
It corresponds to the row number on the periodic table (between 1-7)
What happens as n increases?
The electrons distance from the nucleus and energy increases
What is the second quantum number called?
Angular Momentum Quantum Number (l)
What does the quantum number (l) indicate?
Indicates shape
What does l equal when dealing with the s-orbital?
l= 0
What does l equal when dealing with the p-orbital?
l= 1
What does l equal when dealing with the d-orbital?
l= 2
What does l equal when dealing with the f-orbital?
l= 3
What is the third quantum number called?
Magnetic Quantum Number (m)
What does the quantum number (m) indicate?
Indicates the number and orientation of orbitals around the nucleus within a subshell (Can be from -l to +l
*When l=0, m=0)
What is the fourth quantum number called?
Spin Quantum Number (s)
What does the quantum number (s) indicate?
Indicates the orientation of an electrons magnetic field.
What does the quantum number (s) tell you?
Whether or not the spin is positive or negative (Can be listed as +½ or -½ or also as ↑ or ↓)
What does each quantum number work to do?
Each quantum number locates the location of an electron a little more specifically.
