Chapter 2 Flashcards
Atomic #=
Atomic #= Z (Mass # )= P^+(number of protons)
Charge=
Charge=P-e
Protons - electrons
Mass=
Mass #= A = protons + neutrons
Notation of an isotope
AZE”, notation where A is the mass number, Z is the atomic number, and E is the element symb
In neutral isotopes
Electrons are equal to protons
Percent abundance formula
(M1)(x) + (M2)(1-x) = M(E)
M1 denotes the mass of one isotope’
x denotes its relative abundance.
The mass of the second isotope is denoted by M2.
M(E) denotes the periodic table element’s atomic mass.
Atomic weight formula
(Percent abundance of isotope 1/100)(mass of isotope 1) + (percent abundance of isotope 2/ 100) (mass iso 2)
Ionic compound
Metal and non metal or polyatomic ion
Covalent
Non mental w non metal
Naming for metals
Prefixes and ide ending
Naming for transition metals
Roman numerals and ide ending or polyatomic name
Prefixes
Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca
Metalloids
B, Si, As, Te, Ge, Sb
Group 1 is called
Alkali metals excluding H
Group 2 is called
Alkaline earth metals
Group 17 are
Halogens
Group 18
are noble gases
Highest reactivity of elements
Bottom left (metals are more reactive as we go down)
Top right (non metals are more reactive as we go up)
Elements by ancient Greeks
Elements
• ancient Greeks believed there were four: Earth, Fire, Water, Air
Who proposed the concept of atoms
Atoms
• Democritus & Leucippos (~400 BC) proposed concept of tiny particles
Alchemy
Alchemy
• attempts to transmute “base” metals (i.e., cheap ones) into gold
• went on for about 2000 years without success…
• …but lead to discovery of many elements & chemicals (e.g., mineral acids)
Extraction of metals from minerals
Extraction of metals from minerals
• geologist Georg Bauer a.k.a. Georgius Agricola (German 1494 - 1555)
Medicinal use of minerals
Medicinal use of minerals
• Philippus Theophrastus) did this & also a lot of synthetic chemistry
What did Robert Boyle do? What did he believe?
• Robert Boyle (English, 1627 - 1691): among first to “measure” things
• did not believe in Greeks’ four elements
• his idea: an element = a substance that cannot be further broken down
• did not believe metals were elements → : he dabbled in alchemy…
Phlogiston: a major scientific dead-end (1667 - mid 1700s)
former theory of combustion in which all flammable objects were supposed to contain a substance called phlogiston, which was released when the object burned. phlogiston was presumed to have negative mass!
Who is the father of modern chemistry and what did he introduce
• Lavoisier = the father of modern chemistry
• introduced systematic terminology & quantitative experimentation
And Law of Conservation of Matter
John Dalton’s atomic theory (1803):
- All matter is made of atoms.
- All atoms of an element are identical. ‹ not exactly true…
3.A given compound always has the same relative #s & types of atoms. - Chemical reactions involve the reorganization of atoms, but the atoms themselves are not changed. except in nuclear reactions.
Marie Curie (1876-1934): atoms made of smaller particles
Discovered one of the pieces of evidence for the fact that atoms are made up of smaller particles
Radioactivity:
= the spontaneous disintegration of some elements’ accompanied by emission of unusual “rays”
J.J. Thomson (1897): electrons in all atoms
J.J. Thomson’s experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged “soup.”
J J Thompson experiments
J.J. Thomson’s cathode ray tube experiment discovered the subatomic particle the electron. Prior to the experiment, it was not known that atoms were composed of further particles. Cathode rays were determined to be composed of negatively charged particles that were smaller than the smallest atom.
Robert Millikan
In the experiment, Milliken allowed charged tiny oil droplets to pass through a hole into an electric field. By varying the strength of the electric field the charge over an oil droplet was calculated, which always came as an integral value of ‘e. ‘
Eugene Goldstein discovered what
Eugene Goldstein discovered positive particles by using a tube filled with hydrogen gas (this tube was similar to Thomson’s tube). This resulted in The positive particle had a charge equal and opposite to the electron. The positive particle was named the proton.