4Early day scientists -Greeks were the first to try and explain chemical changes.Believed that all matter consisted of four basic things. (fire, air, water and earth)
5Democritus Greek, 460-370 B.C. Created the word atomus (atom) Believed everything was composed of atomsProposed that the world is made up of empty space and atoms.He believed everything was composed of this and the atom was indivisible.
6Alchemy -A pseudo science, purpose of the science was to attempt to make gold.Such elements as Hg, S, and Sb were discovered due to this science.
7John Dalton (1766-1844) - English - first to prepare a table of relative atomic weights and the Law of multiple proportions.Dalton’s early day symbols
8Law of multiple Proportions - when two elements form a series of compounds , the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers.Ex: NO and NO2
9Law of Multiple Proportions 2Law of Multiple Proportions92.1
10Dalton's Atomic Theory - 1. Each element is made up of tiny particles called atoms.2. The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.3. Chemical compounds are formed when atoms combine with each other. A given compound always has the same relative numbers and types of atoms.4. Chemical reactions involve reorganization of the atoms -- changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction.
11J.J. ThomsonEnglish, ( )In 1897 discovered the particle the electron.Discovered it by using a cathode ray.
13Cathode Ray TubeA stream of electrons is produced at the negative pole of an applied electric field.The electron was isolated using this device.
14J.J. Thomson, measured mass/charge of e- (1906 Nobel Prize in Physics) 142.2
15George J. Stoney Don’t take down Irish, 1826-1911 In 1891, he proposed the term 'electron' to describe the fundamental unit of electrical charge, and his contributions to research in this area laid the foundations for the eventual discovery of the particle by J.J. Thomson in 1897.Don’t take down
16The modern view of the atom was developed by Ernest Rutherford of New Zealand (1871-1937).
17(1908 Nobel Prize in Chemistry) particle velocity ~ 1.4 x 107 m/s(~5% speed of light)atoms positive charge is concentrated in the nucleusproton (p) has opposite (+) charge of electronmass of p is 1840 x mass of e- (1.67 x g)172.2
18Ernest Rutherford Canterbury University in Christchurch, NZ Rutherford laboratory
20Ernest Rutherford New Zealand, ( 1871 - 1937) Named the alpha and beta particles and the gamma ray.Named the proton and is known for the use of the foil method to detect the proton.Conducted the gold foil experiment , which led to the discovery of the nucleus
21James ChadwickEnglish, ( )Isolated the neutron in 1932.
23ATOM COMPOSITION The atom is mostly empty space protons and neutrons in the nucleus.the number of electrons is equal to the number of protons.electrons in space around the nucleus.extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water.
24Proton - comes from the Greek meaning " the primary one". Positive charged particle equal in magnitude to the electron's negative charge.Mass = x g.
25Atomic Number tells the number of protons. 13 Atomic number Al Atom symbol26.981Atomic weight
26Neutron -neutrally charged particle which has the same mass as the proton.Mass = x g.To find the number of neutrons(Mass # - Atomic # = # neutron)
27Electron -Negatively charged particle found orbiting the nucleus of the atom.An atom's activity is primarily determined by the electron.Occupies most of the atom's volume.In a neutral atom , # of electrons = # protons.
28ATOMIC COMPOSITION Summary Protons+ electrical chargemass = x grelative mass = atomic mass units (u)Electronsnegative electrical chargerelative mass = uNeutronsno electrical chargemass = u
29Antoine Lavoisier French, (1743 - 1794) First to truly explain the true nature of combustion.Used quantitative measurements in his experiments, which led to the Law of conservation of mass.
30Antoine Lavoisier Lavoisier named phlogiston (oxygen). The word oxygen comes from the Greek meaning " to form an acid".Was beheaded during the French Revolution.
31Law of conservation of mass - states that mass is neither created nor destroyed.
32Joseph Proust French, (1754 - 1826) Came up with the principle known as the Law of definite proportions.
33Law of Definite Proportions States that a compound always contains exactly the same proportions of elements by weight.
34Benjamin Franklin American (1706 - 1790) Discovered two types of electric charge.He named them positive and negative.Experiments showed that like charges repel each other and unlike charges attract each other.
37Georg Baurer1500’s - GermanDevelopment of metallurgy
38Paracelsus – 1500’s - SwissStudied the medicinal application of minerals.
39Robert Boyle English, (1627- 1691) First person to perform truly quantitative physical experiments.
40Georg Stahl ( ) GermanBelieved a substance called phlogiston flowed out of burning materials.
41Joseph Priestley (1733- 1804) English First to isolate “Phloiston”, oxygen, by heating mercuric oxide.First to observe graphite as an electrical conductor.
42PriestleyObserved a gas being given off during the fermentation of grains, (CO2), this gas could be dissolved in water to make a drink called seltzer.
43Atomic WeightThis tells us the mass of one atom of an element relative to one atom of another element.Tells the number of protons and neutrons in an atom.The average mass of an element.Standard = carbon
47Joseph Guy- Lussac (1778-1850) French Performed experiments in which he measured the volume of gases if the temperature and pressure were held constant.He was the co-discoverer of boron.
48He and Jean-Baptiste Biot made a hot-air balloon ascent to a height of 6.4 kilometres in an early investigation of the Earth's atmosphere. He wanted to collect samples of the air at different heights to record differences in temperature and moisture.
49Particles in a MoleAvogadro’s NumberAmedeo Avogadrox 1023There is Avogadro’s number of particles in a mole of any substance.
50Amadeo Avogadro Italian, (1776 - 1856) Avogadro's Hypothesis - states that at the same temperature and pressure, equal volumes of different gases contain the same number of particles.
61Radioactive Particles Alpha – has a +2 charge, a charge twice that of the electron and with opposite sign.A piece of paper will deflect it.
62Radioactive Particles Beta – High speed electron.A piece of aluminum foil will deflect it.
63Radioactive Particles Gamma – High energy light.One foot of solid concrete will stop it.
64Nucleus Center of atom containing the proton and neutron. Makes up most of the atom’s mass.Protons and neutrons are very tightly packed in the nucleus.Very dense.
65Pierre and Marie Curie Poland-(1867-1934), France-(1859 - 1906) Worked to isolate polonium and radium from pitch blend.Marie is the only person to have won the Nobel Peace Prize in Science twice.
66Michael Faraday English (1791- 1867) Showed that the same quantity of electric current caused different quantities of different metals to deposit, and postulated that those quantities were related to the relative masses of the atoms of those elements.
68Atomic Mass Unit (amu) - equals 1/12th of the mass of an atom of carbon with 6 protons and 6 neutrons.(To convert to grams use x g = 1 amu)
69Problem :How many neutrons , electrons , and protons does the following element have and what is this element?X (The top number tells the atomic mass and the bottom number the atomic number.P+ = E- = No = = 146The element is Uranium.
70Problem:What is the mass number of a fluorine atom with ten neutrons? Such an atom has a mass of amu. What is the mass in grams?9 p no = mass number 19. ( )amu x gamu=3.156 x g
71Hey mom he doesn’t have feathers. It’s fur, f-u-r.
72Isotopes -atoms with the same number of protons but different number of neutrons.Ex: Mg would have 14 neutrons.
73Find the number of neutrons. 10846 PdIs this an isotope?Why or why not?
74IsotopesAtoms of the same element (same Z) but different mass number (A).Boron-10 has 5 p and 5 n: 105BBoron-11 has 5 p and 6 n: 115B10B11B
7511H 21H 31H Hydrogen Isotopes Hydrogen has _____ isotopes 1 proton and 0 neutrons, protium11H1 proton and 1 neutron, deuterium21H1 proton and 2 neutrons, tritiumradioactive31H
77Isotopes & Their Uses 9943Tc Emits gamma rays Heart scans with radioactive technetium-99.9943TcEmits gamma rays
78Masses of Isotopes determined with a mass spectrometer
7910B11BIsotopesBecause of the existence of isotopes, the mass of a collection of atoms has an average value.Average mass = ATOMIC WEIGHTBoron is 19.9% 10B and 80.1% 11B. That is, 11B is 80.1 percent abundant on earth.For boron atomic weight= (10.0 u) (11.0 u) = u
80Isotopes & Atomic Weight Because of the existence of isotopes, the mass of a collection of atoms has an average value.6Li = 7.5% abundant and 7Li = 92.5%Atomic weight of Li = ______________28Si = 92.23%, 29Si = 4.67%, 30Si = 3.10%Atomic weight of Si = ______________
81Problem:Silver has 2 isotopes , one with 60 neutrons and the other with 62 neutrons.What are the mass numbers and symbols of these isotopes?Ag and Ag
82ProblemBromine has 2 naturally occurring isotopes, one with a mass of amu and a percent abundance of 50.69%.The other isotope, of mass amu has a percent abundance of %. Calculate the atomic mass of bromine.(.5069 x amu) + ( x amu) = amu
83Enrico FermiItalian,Successfully split an uranium atom in the first nuclear fission reaction
84Niels BohrDanish, ( )Compared the motion of electrons to the motion of the planets orbiting the sun.Electrons in motion enable them to overcome the attraction of the positive attraction of the nucleus.
115Metalloids -have properties of both metals and non - metals. Located along zig - zag line.B, Si, Ge, As, Sb, Te
116Dmitri Mendeleev Russian, (1834 - 1907) Arranged the elements on the periodic table according to their properties and atomic weight.Others who suggested some form of periodic table were Chancourtois, Newland, and Meyer.
117Periodic TableDmitri Mendeleev developed the modern periodic table. Argued that element properties are periodic functions of their atomic weights.We now know that element properties are periodic functions of their ATOMIC NUMBERS.
118H.G. MoseleyEnglish ( )Arranged the elements according to atomic #.Died in WWI
129Bismuth -last element in Periodic Table that is not radioactive.
130Phosphorus Phosphorus first isolated by Brandt from urine, 1669 exists as P4 innature, whitephosphorus.
131Boron in Death ValleyDeath Valley has been a major source of borax ( a washing powder )and other boron-containing minerals.Borax was transported out of Death Valley, where it was mined by wagons pulled by teams of 20 mules.
132Gems & MineralsSapphire: Al2O3 with Fe3+ or Ti3+ impurity gives blue whereas V3+ gives violet.Ruby: Al2O3 with Cr3+ impurity
133Distillation -is a widely used method for separating mixtures, mostly liquids, based on differences in their boiling points. A liquid is boiled, capturing and cooling the resultant hot vapors, and collecting the condensed vapors.
134Simple Distillation: Apparatus Put in boilingstone!
135Correct Thermometer Placement Thermometer must be below this level