Chapter 11 Introduction of Atoms Name: ________________ Class: ___________

In the Beginning… 440 BCE… first atomic theory by Democritus History of the atom: https://www.youtube.com/watch?v=NSAgLvKOPLQ In the Beginning… 440 BCE… first atomic theory by Democritus Atom: Greek meaning “not able to be divide” Small hard particles that make up stuff (matter) Countered by Aristotle, stated never end up with something that cannot be divided

Dalton’s Theory John Dalton came up with the new theory 1700’s scientists learn elements combine in certain proportions based on mass 1803 theory All substances made up of atoms Atoms of the same elements are exactly alike Atoms join with other atoms to make new substances (Not quite correct)

We’re getting closer…. J.J. Thomspon discovered atoms are composed of smaller particles Discovered negative particles which he named ELECTRONS Plum-Pudding Model: electrons are located all around an atom

Rutherfords Thoery 1909: experimented with “plum pudding” and discovered atoms more of a solid substance 1911: Revised theory to state center of atom has a nucleus (dense positively charged area) and electrons surround and are repelled by nucleus

Bohr’s Idea 1913: electrons move around the nucleus in certain paths, energy levels Electron can “jump” paths

Schrodinger and Heisenberg Idea Explained the nature of electrons in added Do not travel in definite paths; paths cannot be predicted Theory states; there are regions in an atom where electrons are likely to be found called clouds

Atoms the smallest part of an element that has all the element’s properties. Composed of PROTONS and NEUTRONS and (found in the nucleus) ELECTRONS that revolve swiftly around the nucleus.

Structure PROTONS are positively charged particles NEUTRONS have no charge, but have mass ELECTRONS are smallest and electrically negative The number of Protons and Electron ARE EQUAL ATOMIC NUMBER is equal to the number of electrons which is also the proton number ALWAYS A WHOLE NUMBER ATOMIC MASS is the number of neutrons and protons. HAS DECIMALS DUE TO NEUTRONS

Electrons and Energy Levels Electrons swarm around the nucleus of an atom in layers “clouds” Each cloud has a minimum and maximum number of electrons it can hold The maximum number of layers is 7 The maximum number of electrons in each level is respectfully inner to outer: 2, 8, 8, 18, 18, 32, and 32

Chapter 12 The Periodic Table Name: ________________ Class: ___________ https://www.youtube.com/watch?v=sWwd5vks9n8

Arrangement of Elements Scientists were needing a way to arrange the elements. 1869: Dmitri Mendeleev arranged elements by increasing atomic mass and discovered a pattern called “PERIODS” Wasn’t a perfect fit, and needed retuning

Periodic Table 1914: Henry Moseley arranged the elements by atomic number Solved the problem of missing elements/spaces in the table Periodic Law: the physical and chemical properties of an element changes with its atomic number

Classifying Atoms Organize the atoms by their elements Classified by similar CHEMICAL CHARACTERISTICS(columns/groups) and INCREASING ATOMIC NUMBER (rows/periods) Location will help you predict how it will react with others in bonding.

Metals Nonmetals Metalloids Found on the left of the periodic table Few electrons in outer shell Solids Nonmetals Right if the “zigzag” line on periodic table Almost complete electron shells Mostly gases at room temperature Metalloids “semiconductors” Border left side of “zigzag” Varying number of electrons in outer shell Share properties of both metals and nonmetals

https://www.youtube.com/watch?v=VgVQKCcfwnU

Decoding the Table Each element has a symbol made from its name; either English or Latin root Rows are the periods that show a pattern of change in physical and chemical properties are you move across left to right Vertical columns are groups/families Similar chemical/physical prosperities

We are Familiy…. Each group of elements share similar properties Most family names are the name of the element at the top of the column Some family names are notable based on certain traits

Alkali Metals Group 1 Most reactive metals, the bottom element, Francium, is the most reactive element known. Stored in oil to keep from reacting with air (moisture) 1 electron in their outermost shell

Alkaline-Earth Metals Group 2 2 electrons in the outermost shell Less reactive than group 1

Group 3 Transition Metals, columns 3 to 12 Less reactive than group 1 or 2 Usually have 1 to 2 electrons in outermost shell, (except mercury) Good conductors of thermal energy and electricity

Lanthanides and Actinides Appear in separate “rows” outside the body of the table Elements have very similar properties Lanthanides: shiny, reactive metals Actinides: radioactive or unstable ELEMENTS HIGHER THAN 94 ARE NOT FOUND NATURALLY; PRODUCED IN LABORATORIES

Boron Group Group #13 Contains 1 metalloid and 4 metal elements 3 electrons in outer level Solids at room temperature Most common element is Aluminum

Carbon Group Group 14 1 nonmetal, two metalloids, 2 metals 4 electrons in the outermost shell Reactivity varies among elements Solid at room temperature

Nitrogen Group Group 15 2 nonmetals, 2 metalloids, and 1 metal 5 electrons in outermost shell Reactivity varies with elements Solid at room temperature (except nitrogen)

Oxygen Group Group 16 Three nonmetals, one metalloid, 1 metal 6 electrons in the outermost level Reactive to other elements All but oxygen are solids at room temperature

Halogens Group 17 Nonmetal elements 7 electrons in outermost shell Very reactive; VIOLENT reactions with alkali metals to form salts; never found by self in nature Poor conductors of electric current

Nobel Gases Group 18 Nonmetal elements 8 electrons in outermost shell; except Helium which is 2 UNREACTIVE Colorless, odorless gases at room temperature

Hydrogen Properties are unique to itself most abundant element in universe 1 electron in outermost shell Colorless, odorless gas at room temperature Low density EXPLOSIVE REACTIONS WITH OXYGEN