Chemistry: Elements of the Periodic Table
Periodic Trends and Element Groups
Chemistry, Science
October 9, 2022
The Periodic Table
Discovery of Periodicity=Johann Dobereiner=1817=triads=groups of three elements with similar properties=Alkali (Li-Na-K), Salts (Cl-Br-I)=triads led to periodicity arrangement of elements=repeating patterns among the elements
John Newlands=Law of Octaves=as elements were arranged by atomic weight, patterns of properties chemical and physical occur after every seventh element in the sequence.
Dimitri Mendeleev=modern form of the periodic table=discovered new elements in gaps and the transition metals that did not fit in with other elements=he arranged elements by atomic mass
Henry Moseley=used x-rays to determine the number of protons in the nucleus, and therefore was able to identify the atomic number of every element=he also arranged elements based on atomic number instead of atomic mass, which determine the properties of each element.
Non-Natural Elements=Transuranium Elements
Periodic Table Symbols=atomic number in top left, name of element above its symbol, atomic mass below in decimal form, valence electrons by column number
Vertical columns=groups or families of elements=valence electrons=1A-8A, 1B-8B
Horizontal rows=periods or series=principal energy levels=1-7
Block groups=s-block (left side), p-block (right side), d-block (center), f-block (bottom)
Metals=Left and center of Periodic table=solid, lustrous-shiny, malleable, ductile, good conductors of electricity. Exceptions=Mn is brittle, Mercury is liquid
Non-metals=Right side of Periodic Table=separated from metals by stair step line=gasses or brittle solids. Exceptions=bromine is liquid, diamond carbon is solid=Nonmetals are poor conductors of electricity
Metalloids=between metals and non-metals on right side of table=metalloids share properties of metals and non-metals=have metallic luster but can be crumbly and brittle and mid-range conductivity between metals and nonmetals
F-block=lanthanide series and actinide series=bottom of table=inner transition metals
Periodic Trends
Atomic Radius=decrease left to right and increase top to bottom
Ionic Radius=varies=cations are smaller, anions are larger than parent atoms=therefore, metal ions are usually smaller than non-metal ions
Ionization Energy=minimum energy required to remove an electron from a neutral atom to make it a cation (+)=ionization energy generally increases from left to right and decreases top to bottom on the periodic table
Electron Affinity=energy required to add an electron to a neutral atom and form an anion (-)=generally increases left to right on the periodic table=electron affinity is the opposite of ionization energy
Electronegativity=measure of the attraction between the nucleus and valence electrons=
Element Families
Hydrogen Family=unique=lightest most abundant element=has property of nonmetals=gas at room temperature=natural hydrocarbons=uses=ammonia
Alkali Family=chemically reactive, positive cations, metallic luster, soft and low density
Alkaline Earth Family=metallic properties, denser, harder, higher melting points than alkalis
Transition Metals
Inner Transition Metals=paramagnetic
Post-transition Metals
Boron Family=3 Valence electrons; Industrial Uses
Carbon Family=4 Valence electrons; carbon compounds are the basis for life and organic molecules. Graphite and diamond are also forms of carbon.
Nitrogen Family=5 Valence electrons; most abundant gas in the atmosphere, ammonia
Oxygen Family=6 Valence electrons; atmospheric gas, most abundant in Earth’s crust, necessary for life, used for combustion
Halogen Family=7 Valence electrons; form salts with metallic ions, very reactive
Noble Gas Family=8 Valence electrons full valence; non-reactive, colorless, odorless, tasteless; helium balloons
Worldview=Do chemical elements originate in stars?
Periodic Trends and Element Groups
Chemistry, Science
October 9, 2022
The Periodic Table
Discovery of Periodicity=Johann Dobereiner=1817=triads=groups of three elements with similar properties=Alkali (Li-Na-K), Salts (Cl-Br-I)=triads led to periodicity arrangement of elements=repeating patterns among the elements
John Newlands=Law of Octaves=as elements were arranged by atomic weight, patterns of properties chemical and physical occur after every seventh element in the sequence.
Dimitri Mendeleev=modern form of the periodic table=discovered new elements in gaps and the transition metals that did not fit in with other elements=he arranged elements by atomic mass
Henry Moseley=used x-rays to determine the number of protons in the nucleus, and therefore was able to identify the atomic number of every element=he also arranged elements based on atomic number instead of atomic mass, which determine the properties of each element.
Non-Natural Elements=Transuranium Elements
Periodic Table Symbols=atomic number in top left, name of element above its symbol, atomic mass below in decimal form, valence electrons by column number
Vertical columns=groups or families of elements=valence electrons=1A-8A, 1B-8B
Horizontal rows=periods or series=principal energy levels=1-7
Block groups=s-block (left side), p-block (right side), d-block (center), f-block (bottom)
Metals=Left and center of Periodic table=solid, lustrous-shiny, malleable, ductile, good conductors of electricity. Exceptions=Mn is brittle, Mercury is liquid
Non-metals=Right side of Periodic Table=separated from metals by stair step line=gasses or brittle solids. Exceptions=bromine is liquid, diamond carbon is solid=Nonmetals are poor conductors of electricity
Metalloids=between metals and non-metals on right side of table=metalloids share properties of metals and non-metals=have metallic luster but can be crumbly and brittle and mid-range conductivity between metals and nonmetals
F-block=lanthanide series and actinide series=bottom of table=inner transition metals
Periodic Trends
Atomic Radius=decrease left to right and increase top to bottom
Ionic Radius=varies=cations are smaller, anions are larger than parent atoms=therefore, metal ions are usually smaller than non-metal ions
Ionization Energy=minimum energy required to remove an electron from a neutral atom to make it a cation (+)=ionization energy generally increases from left to right and decreases top to bottom on the periodic table
Electron Affinity=energy required to add an electron to a neutral atom and form an anion (-)=generally increases left to right on the periodic table=electron affinity is the opposite of ionization energy
Electronegativity=measure of the attraction between the nucleus and valence electrons=
Element Families
Hydrogen Family=unique=lightest most abundant element=has property of nonmetals=gas at room temperature=natural hydrocarbons=uses=ammonia
Alkali Family=chemically reactive, positive cations, metallic luster, soft and low density
Alkaline Earth Family=metallic properties, denser, harder, higher melting points than alkalis
Transition Metals
Inner Transition Metals=paramagnetic
Post-transition Metals
Boron Family=3 Valence electrons; Industrial Uses
Carbon Family=4 Valence electrons; carbon compounds are the basis for life and organic molecules. Graphite and diamond are also forms of carbon.
Nitrogen Family=5 Valence electrons; most abundant gas in the atmosphere, ammonia
Oxygen Family=6 Valence electrons; atmospheric gas, most abundant in Earth’s crust, necessary for life, used for combustion
Halogen Family=7 Valence electrons; form salts with metallic ions, very reactive
Noble Gas Family=8 Valence electrons full valence; non-reactive, colorless, odorless, tasteless; helium balloons
Worldview=Do chemical elements originate in stars?