Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
73 Cards in this Set
- Front
- Back
|
The earliest ideas about matter came from who?
|
The Greeks
|
|
|
What where Democritus's views of matter?
|
Reasoned that all matter could be continuously divided until you reached a size that could no longer be divided
Called these indivisible particles atomos - "uncuttable" |
|
|
What where Aristotle's views of matter?
|
All matter is composed of only four elements - earth, air, water, and fire in varying ratios
His ideas influenced Chemistry and Alchemy for nearly 2,000 years |
|
|
Who is John Dalton?
|
An English schoolteacher from the 1800s
|
|
|
Why does Dalton succeed over Democritus?
|
Because he had scientific evidence
|
|
|
Who was Antoine Lavoisier? What did he do? What did he develop?
|
Father of modern Chemistry
Conducted chemical reactions with careful measurements Developed the Law of Conservation of Mass |
|
|
What did Joseph-Louis Proust propose and do?
|
Proposed the Law of Definite Proportions
Decomposed metal oxides into the elements that compose them The elements in any compound are present in a fixed proportion by weight |
|
|
What did Joseph Louis Gay-Lussac do?
|
Deduced that gases at constant temp. and pressure combine in very simple numerical ratios
Results support the Law of Definite Proportions |
|
|
What is the Law of Multiple Proportions? Who proposed it?
|
Proposed by John Dalton
Elements can combine in more than one whole number ratio Explains why only a small number of elements can form a wide variety of compounds - For example: Hydrogen and Oxygen can combine to form water or Hydrogen peroxide |
|
|
What was Dalton's atomic theory?
|
All matter is made of tiny particles, called atoms
Atoms of the same element are identical. Atoms of an element are different from atoms of any other element Atoms are neither created nor destroyed in chemical reaction Atoms of different elements combine in simple whole number ratios to form compounds In a chemical reaction, atoms are separated, combined, or rearranged |
|
|
What is Scientific law?
|
states an observation about things in nature that always occur
|
|
|
What is a theory?
|
explain natural phenomena, considered valid or "proven," if it can used to make predictions that are proven true, can be modified as new data becomes available
|
|
|
What did Pierre and Marie Curie do and discover?
|
Pierre and Marie Curie worked with "pitchblende," an ore of uranium
Discovered polonium and radium In 1903 they were awarded the Nobel prize in physics along with Henri Becquerel |
|
|
What did Henri Becquerel do and discover?
|
Studied natural phosphorescence - glow in the dark
Discovered natural radioactivity from his studies of the phosphorescence of natural uranium salts Shared 1/2 of the 1903 Nobel prize with the Curies |
|
|
What did Wilhelm Roentgen do?
|
In 1895 he discovered x-rays
Received the 1st Nobel prize in 1901 |
|
|
What is radiation and what are the three types of it?
|
Energy and sometimes particles are released by the nuclei of unstable atoms
Alpha α - a stream of He nuclei, consists of 2 protons and 2 neutrons Beta β - stream of electrons, more energy Gamma γ - energy, no mass, no charge, extremely energetic |
|
|
Who conducted the Gold Foil experiment?
|
Conducted by Ernest Rutherford in 1911
|
|
|
What was the experimental design of the Gold Foil Experiment?
|
Polonium emits alpha particles through a slit in a fluorescent screen
The particles are directed at a very thin piece of gold foil Light is emitted when an alpha particle hits the fluorescent screen Rutherford expected the particles to pass through the foil |
|
|
What where the results of the Gold Foil Experiment?
|
As expected, most of the particles passed straight through the foil and hit the back of the screen
The surprising result was that some of the particles were deflected at large angles Some of the particles were deflected straight back at the source |
|
|
What was the conclusion of the Gold Foil Experiment?
|
Most of the atom is empty space with a dense, positively charged core containing most of the mass
More than 99% of the atomic mass is in the nucleus |
|
|
Describe the proton and name who discovered it.
|
Discovered 5-6 years after the electron - generally credited to Ernest Rutherford
Henri Moseley - experimenting with x-rays found atomic numbers Positive charge Protons are ~2,000 times more massive than an electron Protons are found in the nucleus |
|
|
Describe the neutron and name who discovered it.
|
Discovered in 1932 by James Chadwick
Neutral Is slightly more massive than a proton Located in the nucleus |
|
|
What is the atomic number?
|
The number of protons/electrons in an atom
|
|
|
Who discovered electrons and when where they discovered?
|
J.J. Thomson in 1897
|
|
|
How where electrons discovered?
|
Using a cathode ray tube, J.J. Thomson saw that when connected to a power source, a beam of light ran through it. This beam was deflected towards the positive pole of a magnet.
|
|
|
Who was J.J. Thomson?
|
He discovered the charge to mass ratio for the electron, discovered that electrons have a negative charge, and received the 1906 Nobel Prize in Physics.
|
|
|
Who was Robert Millikan?
|
He performed the Oil Drop experiment. Discovered that it was possible to calculate the mass of an electron.
|
|
|
What was the oil drop experiment?
|
Performed by Robert Millikan. Measured the actual electrical charge on an electron.
|
|
|
What was the "Plum Pudding Model?"
|
Created by J.J. Thomson.
With the discovery of the electron, a new model of the atom needed to be created. The "Plum Pudding model" had a positive material with negatively charged electrons embedded in it. |
|
|
What are the masses of the 3 parts of an atom?
|
Proton - 1 amu
Neutron - 1 amu Electron - 1/2000 amu |
|
|
What is an isotope?
|
Atoms of the same element (have the same number of protons) with a different number of neutrons
|
|
|
What is the mass number?
|
the number of protons + the number of neutrons
|
|
|
How do you calculate the number of neutrons?
|
Mass number - number of protons(atomic number)
|
|
|
Isotopes of an element have identical what?
|
Physical and chemical properties
|
|
|
What is the number "16" in the NAME of the isotope Oxygen - 16?
|
The mass number
|
|
|
How are the numbers arranged to write out the SYMBOL for the isotope of Oxygen?
|
The mass number (16) goes over the atomic number (8)
Big over small |
|
|
What are the three types of hydrogen and how many neutrons does each one have?
|
Protium - 0 neutrons (H 1)
Deuterium - 1 neutron (H 2) Tritium - 2 neutrons (H 3) |
|
|
How do you find the mass of an element on the periodic table?
|
It is the weighted average of the mass of each isotope and its percent abundance in nature
|
|
|
What are the 5 types of decay?
|
alpha decay, beta decay, gamma radiation, positron emissions, K-capture
|
|
|
What is alpha decay?
|
occurs in elements with atomic numbers that are greater than 82
You add a 4/2 He and the isotope that is 4 less/2 less than the original |
|
|
What is beta decay?
|
elements with too many neutrons; a neutron converts to a proton and
an electron is ejected from the nucleus you increase the bottom number (atomic number) by 1 and the top number (mass number) stays the same and you add a beta symbol to equal the original |
|
|
What is gamma radiation?
|
- often emitted with a gamma or beta particle
- doesn’t affect mass or charge so it is usually omitted from the equation - unstable nuclei have too much energy and need to get rid of it |
|
|
What are positron emissions?
|
- an anti-electron
- anti-matter; every particle has a correlate anti-matter particle |
|
|
What is K-capture?
|
- electron capture
- an electron is pulled into the nucleus - proton + electron → neutron |
|
|
What is nuclear fission?
|
- 1 large nucleus is split into 2 smaller nuclei
- U + Pu bombs use fission reactions - large amount of energy are given off - radioactive isotopes are blown into the atmosphere and fall out for months afterward - “Radioactive fallout” |
|
|
What is nuclear fusion?
|
- 2 smaller nuclei are combined to form 1 atom with a larger nucleus
|
|
|
What is radioactivity?
|
Atoms that are radioactive have unstable nuclei
|
|
|
How is the stability of an isotope determined?
|
by the ratio of protons to neutrons
|
|
|
Every element above what is radioactive?
|
83
|
|
|
Radioactive decay is measured in what?
|
half-life
|
|
|
What is half-life?
|
the amount of time required for ½ the radioactive sample to decay
|
|
|
What is the electromagnetic spectrum?
|
energy that travels through space in a wave
|
|
|
What is the origin?
|
starting point for the wave
|
|
|
What is the crest?
|
Part of the wave above the origin
|
|
|
What is the trough?
|
Part of the wave below the origin
|
|
|
What is amplitude?
|
the distance between the origin and the crest
|
|
|
What is wavelength? What is its symbol?
|
the distance between corresponding points on adjacent waves
λ - lambda (symbol for wavelength) |
|
|
What is frequency? What is it measured in? What is its symbol?
|
the number of waves to pass a given point in a second; measured in Hertz (Hz)
v - nu (symbol for frequency) |
|
|
What is the speed of light?
|
3.00 x 10^8 m/s
|
|
|
What is the equation for wavelength and frequency?
|
C = λv
C - speed |
|
|
What is the equation to solve for the wavelength?
|
C/v = λ
C - speed |
|
|
What is the equation to solve for the frequency?
|
C/λ = v
C- speed |
|
|
What is a radiowave?
|
between 10^4 and 10^-2
AM and FM (T.V.) |
|
|
What are microwaves?
|
between 10^-2 and 10^-4
used for cooking and communications |
|
|
What is infrared?
|
between 10^-4 and 10^-6
used for night vision and heat lamps |
|
|
What is visible light?
|
between 10^-6 and 10^-8
R O Y G B I V |
|
|
What is ultraviolet?
|
between 10^-8 and 10^-10
used for tanning and sterilizing materials |
|
|
What are x-rays?
|
between 10^-10 and 10^-12
used for medical imaging |
|
|
What are gamma rays?
|
after 10^-12
used for cancer treatment |
|
|
What did Planck do?
|
Proposed that electromagnetic radiation is given off in small bundles or packets of energy called quanta or photons
|
|
|
What was Planck's hypothesis?
|
that the energy of a photon is directly proportional to the frequency of the photon
|
|
|
What was Planck's equation?
|
E=hv
E - enegy (J) h - Planck's constant v - frequency |
|
|
What was Planck's constant?
|
6.63 x 10^-34 J/Hz
|
