Periodic Table

People Mendeleev-Russian scientist that published the first modern PT based on atomic mass. Moseley-British scientist that rearranged the PT by atomic number

Element Squares Atomic Number: number of protons in atom Symbol: 1-2 letter abbreviation Element name Electron Arrangement Atomic mass: weighted average of isotopes of atom 6 C Carbon 1s 2 2s 2 2p

Periods Horizontal rows 7 periods Periods correspond w/ # of energy levels an element has The lanthanide and actinide series (on bottom) are pulled out and placed on the bottom to save space.

Groups/Families Vertical columns 18 groups Also called families because each group has similar properties because they have the same # of e- in the outer energy level.

Metals Solid Shiny Good conductors of heat and electricity Malleable Ductile Usually corrode Usually have 1, 2, or 3 valence e-

Nonmetals Can be solids, liquids or gases Dull (not shiny) Brittle, powdery Poor conductors Usually 5, 6, 7, or 8 valence e-

Metalloids Have properties of both metals and nonmetals Next to zig-zag line Often used as semiconductors in computers B, Si, Ge, As, Sb, Te, At

Alkali Metals Group 1 Highly reactive Soft, shiny, silver- white Good conductors 1 electron in outer energy level which they like to give up 1 valence electron Li Lithium Na Sodium K Potassium Rb Rubidium Cs Cesium Fr Francium

Alkaline Earth Metals Group 2 Highly Reactive (but less than Group 1) Soft, silver-white, shiny Give off bright colors when burned 2 electrons in outer most energy level 2 valence electrons Be Beryllium Mg Magnesium Ca Calcium Sr Strontium Ba Barium Ra Radium

Transition Metals Found in middle of PT 3B-12B Not as reactive as Groups 1 and 2 Complex chemistry – number of electrons they give up can vary Number of valence electrons varies

Halogens Group 17 (7A) Tends to gain 1 electron to fill up its outer energy level Very reactive Most reactive nonmetals Mostly gases 7 valence electrons F Fluorine Cl Chlorine Br Bromine I Iodine At Astatine

Noble Gases Group 18 (8A) Gases Unreactive because outer energy level is full of electrons Also called “inert” 8 valence electrons He Helium Ne Neon Ar Argon Kr Krypton Xe Xenon Rn Radon

Lanthanide Series Classified as Rare Earth Metals Found naturally on earth Soft, silver-white malleable metals with high luster (shine) and conductivity. Very reactive Found on bottom of PT

Actinide Series Radioactive Metals Most are man made Found on bottom of PT

Label on your Periodic Table MetalsBlue (or your own code) NonmetalsRed Metalloids (stair step)Green Valence electrons Group Number (Use 1A – 8A system) Period Number Transition Metals Halogens Noble Gases Alkali Metals Alkaline Earth Metals Rare Earth Elements –Lanthanide Series –Actinide Series

Electrons Electrons are found circling the nucleus at extremely fast speeds. The reason they are not pulled into the nucleus is because of how fast they are moving.

Electron Discovery J. J. Thompson 1897 Cathode Ray ‘Plum Pudding’ model of the atom. Negatively charged e- are plopped into a positively charged material. (like plums in pudding)

Mass of an Electron 1909 Robert Millikan Oil Drop Experiment Experimentally Determined the mass and electric charge of an e-

Niels Bohr 1913 Discovered energy levels Believed e- moved in definite paths around the nucleus. Path is determined by how much energy an e- has. An e- can gain or lose energy to move to another level.

Present Day Wave Model There is no definite path around the nucleus It is impossible to determine the exact location of an e- You can guess about the location based on how much energy the e- has Electrons behave both as a particle and a wave.

Energy Levels Electrons do not travel around the nucleus in fixed orbits. Electrons move in an area known as the electron cloud. The electron cloud is a region in which electrons are likely to be found. Within the electron cloud, electrons are arranged in energy levels. Energy levels represent the most probable location in which an electron can be found. An energy level should not be confused with a specific path. Electrons do not have a specific path. In fact, scientists can speak only of the chances or probability, of finding electrons at various locations- not of their exact position.

Energy E- near the nucleus require lower energy E- away from the nucleus require more energy E- can jump from one level to another by gaining or losing energy Because of this, an e- is most likely to be found in the 1 st energy level, closest to the nucleus. Energy Level Max. # of e- Energy 12Lowest Higher

Valence Electrons The e- in the outer most energy level are called valence electrons. The number of valence e- determines how an element bonds. The groups are arranged so that 1A-8A (skip He) correspond with the number of valance e-.

Valence cont. How many valence electrons do the following elements have? Ca _______Si _________ Li ________Cl _________ P ________F __________ Ar _______B __________

Answers Ca= 2 Si = 4 Li = 1 Cl = 7 P = 5 F = 7 Ar = 8 B = 3

Electron Dot Diagrams Write the element symbol Use dots to represent the # of valence e- Make a square with up to 2 dots on each side, up to a total of 8.

Sublevels Within the energy levels, electrons occupy specific sublevels. S- group 1, 2 (2 e-) P- group (6 e-) D- group 3-12 (transition metals) (10 e-) F- Lanthanide, Actinide (14 e-)

Energy The energy levels don’t fill up perfectly in order. E- fill up in order of energy. The 4s sublevel requires less energy than the 3d sublevel, so e- fill it first. The correct order follows the Periodic Table.

Electron Configuration on the Periodic Table

Electron Configuration Write the electron configuration of the following elements: Aluminum ___________________ Chlorine _____________________

Answers Aluminum: 1s 2 2s 2 2p 6 3s 2 3p 1 –Noble gas [Ne]3s 2 3p 1 Chlorine: 1s 2 2s 2 2p 6 3s 2 3p 5 –Noble gas [Ne] 3s 2 3p 5