* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Science notes on Atoms, Periodic table
Photoelectric effect wikipedia , lookup
Nuclear transmutation wikipedia , lookup
Low-energy electron diffraction wikipedia , lookup
Bent's rule wikipedia , lookup
X-ray photoelectron spectroscopy wikipedia , lookup
Electrochemistry wikipedia , lookup
Electrical resistivity and conductivity wikipedia , lookup
Livermorium wikipedia , lookup
X-ray fluorescence wikipedia , lookup
Resonance (chemistry) wikipedia , lookup
Hypervalent molecule wikipedia , lookup
Abundance of the chemical elements wikipedia , lookup
Boron group wikipedia , lookup
Atomic orbital wikipedia , lookup
Alkaline earth metal wikipedia , lookup
Bond valence method wikipedia , lookup
History of chemistry wikipedia , lookup
Molecular orbital diagram wikipedia , lookup
Electronegativity wikipedia , lookup
Chemical element wikipedia , lookup
Atomic nucleus wikipedia , lookup
Periodic table wikipedia , lookup
History of molecular theory wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
Chemical bond wikipedia , lookup
Metallic bonding wikipedia , lookup
Electron configuration wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
Extended periodic table wikipedia , lookup
Science notes on Atoms, Periodic table Combustion When we burn sugar in our body it is called cellular respiration. When we burn it quickly it is called combustion. The 3 things that are needed for combustion are: 1. Fuel 2. Oxygen 3. Heat (^this is also called the circle of fire) The oxygen can be replaced with something that acts like oxygen, hence it does not necessary mean that it HAS to be oxygen, this is why its called the oxidizing agent. The fuel can be sugar, gas, oil etc …anything that can react with oxygen, usually it has a lot of carbon The heat is needed to get the reaction going. (ignition temperature) During combustion, energy is always released The Atom 1st discovered & named by Democritus, who believed it was a small indivisible particle of matter. Aristotle believed that it was infinitely divisible (you could keep on cutting it forever). He also believed that everything was composed of 5 elements: water, earth, fire, air & aether John Dalton then concluded that there must be particles of different elements. All the atoms of a single element are identical All atoms of different elements are different Atoms combine to form compounds Thomson discovered electrons (negatively charged particles in the atom) Rutherford, using radiation, concluded that Atoms are empty At the center of an atom is a positively charged nucleus (protons) Electrons orbit around the nucleus Periodic Table Dmitri Mendeleev created it. g -number of protons: 20 -number of neutrons: 20 (40-20) -number of electrons: 20 The # of protons= # of electrons. The # of neutrons is the atomic mass minus the # of protons. To draw the model of an element remember that the protons and neutrons go in the center and the electrons go on the orbitals. The first orbital can hold only 2 electrons, while every other one can hold up to 8 electrons. Example: Boron ( 5 protons, 5 neutrons, 5 electrons) Quick Diagram Every element in the periodic table is classified in a group; metals, non-metals or metalloids. Metals Found at the left side of the staircase that starts at 13 Conducts electricity & heat Ductile & malleable Non-Metals Found on the right of the staircase that starts at 13 (hydrogen is included) Poor conductors of electricity & heat Metalloids Basically includes all the elements along the staircase at 13 (boron, silicon, germanium, arsenic, antimony, tellurium & astatine) They have both metal & non-metal properties Sometimes good conductors of electricity The elements are also placed into groups based upon similar chemical reactions. All elements in the same chemical group share similarities during chemical reactions. The Alkali metals Elements along the first column except for hydrogen (lithium, potassium…) They are highly reactive & must be stored in oil Are soft & malleable The Alkali earth metals Elements along the second column (beryllium, magnesium, calcium…) They are somewhat reactive but less reactive than the alkali metals Highly malleable Burns easily if there is heat The Halogens Elements along the 7th column (fluorine, chlorine…) Non-metal Powerful disinfectants React to form compounds Noble Gases Elements along the 8th column (helium, neon…) Very stable, rarely react Colorless & odourless “Periods” are referred to the rows in the periodic table. Balancing Equations To balance solutions we can’t ever change or touch the exponent attached to the element. NH3 + Cl2 HCl + N2 (not balanced) 2NH3 + 3Cl26HCl+ N2 (balanced) NaOH Na +O2 + H2O 12NaOH 12Na+ 3O2+ 6 H2O NaI + Pb(NO3)2 PbI2 + NaNO3 NaI + PbNO6 PbI2 + NaNO3 2 NaI + PbNO6 PbI2 + 2NaNO3 (balanced) Lewis dot diagram Displays the valence electrons in an element Valence electron means number of electrons on the outer most orbital of an element Valence electrons are equal to the number of the column ( ex: hydrogen has 1, carbon has 3..) Valence number is the amount of levels an element has and is equal to the number of the row ( ex: lithium has 2 layers, potassium has 4…) Covalent bonds When a metal element & a non-metal element bond together they form iconic bonds. Naming iconic bonds: name the element and then name the second element except end it with an “ide” KBr potassium bromide NaCo2 Sodium carbonate NaF Sodium fluoride Non-metals want to receive electrons whereas metals want to give away electrons. The valence electrons of an element determines how many electrons an element wants give or take. When the two elements bond together the exponents switch over (cross over rule) Examples: Lithium is a metal, it has 1 valence electron therefore it wants to give away 1 electron. All metals want to have 8 valence electrons. Carbon is a non-metal, it has 6 valence electrons & it wants to have 8 therefore it takes 2 valence electrons. Li1+ & C2- cross over rule & becomes Li2C (lithium carbonate) Co3+ & CO2- 3 Co2(CO3)3 (Cobalt carbon oxide) When a non-metal element and a non-metal element bond together they form covalent bonds. When naming covalent bonds you must include the # of the exponent. The crossover rule also applies here. C2 & O CO2 (carbon dioxide) 1=mono 2= di 3=tri 4=tetra 5=penta 6=hexa 7=hepta 8=octa 9=nona 10=deca ex: N2O3 (dinitrogen trioxide) Moles 1 mole of an element is basically its atomic mass. 2 moles of an element would be 2 times its atomic mass. 4Fe2S …its mass? 8 x atomic mass of Fe + atomic mass of S = 8(56) + 4(32) = 576 How many moles is 100 grams of sulfur? x= 100/32 = 5.06 How many moles is 182.305 g of HCl? 1(H) + 35 (Cl) = 36 (so 1 gram of HCl is 36) X= 5.06 Sometimes they give you formulas and ask you to answer specific questions. To get the answer 1. Make sure the formulas are balanced (if they aren’t balance them) 2. Create the table 3. Circle the elements that you need 4. Set up a proportion and solve to find the answer Example: 2NaOH + H2SO4 2H2O + Na2SO4 How many grams of sodium sulfate will be formed if you start with 200 grams of sodium hydroxide? 1. They are balanced 2. 3. 4. 80 grams of sodium hydroxide creates 142 grams of sodium sulfate, so how many grams of sodium sulfate would be created if there were 200 grams of sodium hydroxide? x= 355 grams ,