Dmitri Mendeleev The Father of the Original Periodic Table (1869). Based on increasing Atomic Mass.

Henry Mosley The Father of the “Modern Periodic Table” arranged on increasing Atomic number. (1914)

Periodic Law Mendeleev saw that when elements were arranged in order of increasing atomic mass the elements with similar properties occurred in repeating patterns. He was able to predict properties of elements that had not been found yet. Henry Mosley (1914) revised the periodic table using the atomic number as the basis for assigning the place on the periodic table.

Periodic Table Basics 7 periods are the horizontal rows A noble gas is at the end of each period 18 groups are the vertical columns Groups have the same number of VALENCE ELECTRONS and SIMILAR PROPERTIES Lanthanide and Actinide Series are broken out from period 6 and 7 because of space requirements

Periodic Law States that the repeating chemical and physical properties of elements change periodically with the elements’ atomic number. Periodic means “happening at regular intervals.” The elements properties repeat in a predictable way.

Rows or Periods Rows or periods are horizontal lines of elements across the periodic table. Their electrons are located in the same energy shell.

Rows or Periods From the left to the right: The are 7 rows with 2 to 32 elements Become less metallic. Become less conductive Noble gas at the end of each row. Atomic number and mass increase (in most cases).

Lanthanides and Actinides They appear at the bottom of the periodic table to keep rows 6 and 7 from being too wide. Lanthanides are shiny and generally reactive transition metals; many are used in making steel. Actinides are all radioactive and unstable. All elements after Uranium are not found in nature but are synthetic or man-made.

Groups or Families Groups or families are vertical columns of elements that have similar chemical and physical properties due to it’s valence electron structure.

Alkali Metals The most reactive metals or group 1. They have 1 valence electron that they would like to give away or share with another element. They are so highly reactive they are not found in nature except reacted with another element. Are all metals, silvery in color, soft can cut with a knife, low density. NaCl, KCl, KBr.

Alkaline Earth Metals Are slightly less reactive than Alkali metals. Group 2 has 2 valence electrons to give away. All are metals, higher density than alkali metals, and silvery in color.

Transition Metals Are the metals of groups 3 through 12. They are less reactive than groups 1 and 2 and difficult to predict their properties. All are shiny, have good thermal and electrical conductivity. They all have either 1 or 2 valence electrons.

Boron Group Boron or group 13 have 3 valence electrons in the outer shell. The group contains one metalloid (B) and 4 metals. Aluminum is the most used metal in this group.

Carbon Group Carbon or group 14 have 4 valence electrons in their outer shell. The group contains one nonmetal (C), 2 metalloids (Si, and Ge), and 3 metals. Carbon is considered the element of life because it is the basis for so many compounds, fats, and proteins, Si and Ge are used in computer chips, and Sn, Pb, and are used for various applications with metals.

Nitrogen Group Nitrogen or group 15 have 5 valence electrons. The group contains 2 nonmetals ( N, P), 2 metalloids (As, Sb), and 1 metal (Bi). Nitrogen makes up 78% of the air we breath. It is reacted with H to make Ammonia which is used in making fertilizers. Phosphorus is very reactive and is found only with other elements it is so reactive.

Oxygen Group Oxygen or group 16 have 6 valence electrons. The group contain 3 nonmetals ( O, S, Se), 1 metalloid (Te), and 1 metal (Po). All except Oxygen are solid at room temperature. Oxygen makes up 21 % of our air and Sulfur is a yellow solid used to make sulfuric acid the most widely used compound in industry.

Halogen Group The halogens or group 17 have 7 valence electrons. They are all nonmetals and are very reactive; so reactive they are never uncombined in nature. They react with Alkali metals to form salts (NaCl, KCl, KBr, KI). They exist as gas, liquid, and solids at room temperature. Bromine and Chlorine are used as disinfectants.

Noble Gases Noble gases or group 18 contain a full set of 8 valence electrons in their outer shell making them extremely stable and very nonreactive. They do not need to lose or gain electrons. Argon is about 1% of the air we breath, neon is widely used for colored lights, argon is used inside light bulbs to extend the filament life, and helium is used to float balloons.

Hydrogen Hydrogen is the most abundant element in the universe and it has 1 proton and no neutrons for an atomic mass of 1.0. Our sun is made mostly of hydrogen and it is very reactive. Hydrogen is a group all to itself. It really does not have properties of any one group of elements.

Helium Helium is the second element on the periodic table. It has 2 protons and 2 neutrons for an atomic mass of 4. Used in balloons and blimps. It is a noble gas and has a full electron shell with only 2 valence electrons. All other periods have 8 valence electrons for their noble gas.

Atomic Particles Proton + charged Neutron 0 charged Electron - charged

Element Info Atomic # = # of protons in the nucleus Chemical Symbol = A single capital letter or Capital letter and lower case letter Chemical Name =Element Name Atomic Mass # = #protons and #neutrons in the nucleus

Formulas Atomic mass - Atomic # = # of Neutrons Atomic Number = protons which tells what the element is.

Proton, Neutron, Electron Info Cannot have a partial proton, neutron, or electron. They must be in whole numbers. The decimal points on the atomic mass on the periodic table is because of the isotopes of that element.