By: Aimee Chavez Atoms & Periodic Table

Properties of Subatomic particles Protons: positive + charge , found in nucleus, Electrons: negative - charge, found outside nucleus Neutrons: 0 charge, found in nucleus,

Atomic Number 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.

A.P.E 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.

Mass Number 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.

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

Isotopes 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 !

Valence Electrons Electrons involved with Chemical Bonds Group 1 = 1 Group 13 -18 minus 10 therefore 18 has 8 Valence Electrons. The maximum V.E. is 8 which is considered stable.

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

Lewis Dot or Electron Dot Diagrams A model of an atom in which each dot represents a valence electron.

Periodic Table 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

Periodic Law Elements are arranged by increasing atomic number. There are patterns of repeating properties. 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.

Groups/Families:

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

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

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

Metalloids Varies with temperature Conduct electricity

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

Alkali Metals Group 1 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

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

Transition Elements Groups 3-12 Most are hard and shiny and good conductors of electricity. They are fairly stable.

Boron Family Group 13 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.

Carbon Family Group 14 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 2nd most abundant element in Earth’s Crust. It combines with oxygen to form silicon dioxide which is found in quartz.

Nitrogen Family Group 15 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.

Oxygen Family Group 16 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 2nd 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.

Halogens Group 17 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.

Noble Gases Group 18 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).

Essential Elements 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)

Essential Elements Functions 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

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

Too Much = Harmful 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.