Elements with similar properties occurred in regular intervals periodic Henry Mosely 1914 rearranged the table based on atomic number once protons were discovered Atomic number number of protons in one atom of the element ID: 757427
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Slide1
Periodic TableSlide2
History
Dmitri Mendeleev (1869) arranged the known elements based on atomic mass
Elements with similar properties occurred in regular intervals (periodic)Slide3
Henry Mosely 1914- rearranged the table based on atomic number once protons were discoveredSlide4Slide5
Atomic number- number of protons in one atom of the element
Chemical symbol- Sometimes one letter, sometimes two letters, first letter is always capitalized
Atomic mass- average mass for all naturally occurring isotopes; this is not the same as mass numberSlide6
Element arrangementSlide7
Metals
left of the zigzag
few electrons in outer energy levelmost are solid at room temperatureshiny, good conductors, ductile (can be made into a wire), malleableSlide8
Nonmetals
right of the zigzag (except hydrogen)
have almost complete or complete outer level of electrons many are gasses at room temperaturedull, poor conductors, not ductile, not malleableSlide9
Metalloids
border the zigzag line
half complete set of electrons in outer levelsemiconductorsshare properties with metals and nonmetalsSlide10
Periods
A period is a row (left to right)
Seven of themproperties like conductivity and reactivity change across the periodDensest elements are in the middleSlide11
Groups
Groups are columns (top to
bottom) 18 groupsAlso called familyElements in the same group have similar physical and chemical propertiesSame number of valence electrons (electrons in the outermost shell)Slide12
Valence electrons allow chemical bonding
Group 1 has 1 valence electron
Group 18 has a full set of valence electronsGroup 1 is very reactive, while group 18 does not react with other elementsSlide13
Main Names
Group 1 = alkali metals
Group 2 = alkaline-earth metalsGroups 3-12 = transition metalsGroups 13-15 = named for top element in that group (ex: carbon group
)
Group 16 =
chalcogens
or
chalogens
(oxygen group)
Group 17 = halogens
Group 18 = noble gasesSlide14
Color The PTE and create a key. Then glue in your notes section.Slide15
Chemical Reactions
Exothermic reactions- energy is released
Product can give off light and/or heatEndothermic reactions- energy is absorbedEnergy is in the reactantsSlide16
During chemical reactions bonds between atoms break. Then, the atoms rearrange to make new substances.
The new substance has different physical and chemical properties that the original.
Examples: precipitate forms, odor change, gas produced, etc. Slide17Slide18
Ways to speed up a reaction
Increasing concentration
Increasing surface area (crushing/grinding)Increase temperature Adding a catalystSlide19Slide20
Chemical formulas
Symbols and numbers that represent substances
Examples: Water = H2O
Salt =
NaCl
Glucose = C
6
H
12
O
6
Baking Soda =
NaHCO
3Slide21
Chemical EquationsSlide22
RAP
Reactants
ProductSlide23
The law of conservation of mass means the same number of atoms must be on both side of the equation.
Coefficient
Subscript Slide24
Video Help
Beginning help:
https://www.youtube.com/watch?v=yA3TZJ2em6gMore examples: https://www.youtube.com/watch?v=eNsVaUCzvLA