By: Aimee Chavez

 Protons: positive + charge, found in nucleus, Protons:  Electrons: negative - charge, found outside nucleus Electrons:  Neutrons: 0 charge, found in nucleus, Neutrons

 The atoms of an element have the same number of protons. Equals the number of Electrons. Each + charge in an atom is equal to the – charge making it neutral. atoms atom

 Atomic Number =  Protons =  Electrons  The atomic number of an element is equal to it’s number of protons which is also equal to it’s number of electrons.

 Sum of protons + neutrons.  Atomic Mass: an average of the mass of all the isotopes from an element. The number we see on the periodic table with a decimal.

 Mass –  Atomic Number =  Neutrons  To find the neutrons of an element you take the mass and subtract the atomic number.

 Atoms of the same element that have different number of neutrons and mass numbers.  Written as: C-14 or Carbon -14 or an isotope of Carbon 14.  ** The 14 is the mass number since Carbon is number 6 and always number 6 !

 Electrons involved with Chemical Bonds  Group 1 = 1  Group 2 = 2  Group minus 10  therefore 18 has 8 Valence Electrons. The maximum V.E. is 8 which is considered stable.

 Electrons move in orbitals around the nucleus.  Energy Level 1 = 2  2 = 8 * there are 2*  3 = 18  4 = 32 

 A model of an atom in which each dot represents a valence electron.

 The arrangement of elements relate to it’s properties and it’s structure.  1789: Lavoisier grouped elements into categories he called metals, non metals, gases, and Earths

 1860’s: Mendeleev arranged elements in rows by increasing mass, elements with similar properties were in same columns, there were blanks for those not yet discovered

 Elements are arranged by increasing atomic number. There are patterns of repeating properties. Elementsatomic  Groups/Families: similar properties and electron configuration, determines chemical properties  Variation across a period, left are most metallic right non metallic, left most reactive metal, right most reactive non metal group 17.

 Solid, Liquid or Gas  Natural or not natural, elements above 93 not natural  Properties: metals, non metals, metalloids

 Most conductors of heat and electricity  All solid at room temperature except mercury  Most are malleable, ductile  Some are very reactive

 A mixture of metals with another metal or nonmetals.  Bronze = copper + tin  Brass = copper + zinc  Stainless steel = Fe + ( carbon, chromium or vanadium )  By combining these elements the properties of the mixture is changed. For example stainless steel is less resistant to rusting.

 Metals are found on the left of the periodic table.  Nonmetals are found on the right of the periodic table.

 Varies with temperature  Conduct electricity

 Hydrogen can not be grouped.  Most commonly found combined with oxygen to produce water.

 1 V.E. extremely reactive  Found in nature only as compounds  NaCl (evaporation sea water or Earth’s Surface)  Reactivity increases from top to bottom

 2 V.E. never uncombined in nature  Mg and Ca are essential for Biological functions  Mg: photosynthesis, bile  Ca: Bones, teeth, plaster casts

 Most are hard and shiny and good conductors of electricity.  They are fairly stable.

 Has 3 V.E.  Boron B = metalloid  Aluminum Al, Gallium Ga, Indium In, Thallium Ti are metals  Aluminum is the most abundant element in Earth’s Crust. It is used for packaging, making gutters and screens.  Boron when mixed with silicon makes a durable glass ware often used in Labs.

 4 V.E.  Carbon C = nonmetal  Silicon Si & Germanium Ge are metalloids  Tin Sn & Lead Pb are metals  Carbon is important for all living organisms and is part of many compounds.  Silicon is the 2 nd most abundant element in Earth’s Crust. It combines with oxygen to form silicon dioxide which is found in quartz.

 5 V.E.  Nitrogen N & Phosphorus P are nonmetals  Arsenic As & Antimony Sb are metalloids  Bismuth Bi is a metal  Nitrogen makes up 80% of our atmosphere.  Phosphorus is not stable as an element therefore in nature is as a compound. Used to make flares and matches.

 6 V.E.  Oxygen O, Sulfur S, and Selenium Se are nonmetals  Tellurium Te & Polonium Po are Metalloids  Oxygen is the most abundant element in Earth’s Crust and 2 nd in Earth’s Atmosphere.  It is important for breathing, cell processes  Sulfur is used to make fertilizers, rubber bands, medicine, and is smelled in rotten eggs.

 7 V.E.  Fluorine F, Chlorine Cl, Bromine Br, Iodine I are nonmetals  Astatine At is a metal  These elements are very reactive.  Fluorine is used to prevent tooth decay.  Chlorine is part of table salt.

 8 V.E.  Helium He, Neon Ne, Argon Ar, Krypton Kr, Xenon Xe, Radon Ra are all nonmetals.  They are all part of Earth’s Atmosphere.  Some of the uses are filling balloons and to make lights glow ( Neon Lights).

 There are 25 elements that are essential to the Human Body.  Six of the major ones make up 99 % of body mass. (H,O.C,N,P,Ca)

 O: releases energy stored in foods, most abundant element in body  H: Chemical Reactions  C: Part of many compounds  Fe: Part of Hemoglobin  I: Chemical reactions  K: Muscle and nerve function, fluid balance  V: Controls blood sugar, forms bones and teeth

 Lead Pb can cause organ damage, learning problems. Lead Pb learning  Mercury Hg can cause brain and nervous system damage Mercury Hg  Arsenic As can cause poisoning Arsenic As

 Sodium Na: needed for water balance and nerve function  can cause high blood pressure  Selenium Se: Used for immune function found in brazil nuts  can cause nerve damage  Zinc Zn : Used for immune function  can cause anemia by decreasing Fe uptake.