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44 Cards in this Set
- Front
- Back
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What did Lavoiser do in the 1790's?
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Composed the first list of the 23 elements known since prehistoric times (gold, carbon, silver, etc.)
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What occurred during the Industrial Revolution (1800s)
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Many new elements were isolated (compounds were broken down)
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In 1860, chemists created a _________ for determining the atomic mass of all elements.
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Standard
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What did John Newlands discover in 1864?
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Law of Octaves
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Law of Octaves
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When elements are arranged by atomic mass, their properties repeat every eighth element
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Why was the Law of Octaves ground breaking and what was the problem with it?
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-Showed first periodic relationship in elements
-Problem was that not all known elements followed this pattern |
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What did both Meyer and Mendeleev discover in 1869?
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Both noticed a connection between atomic mass and properties of elements. They arranged elements in order of increasing atomic mass and put elements with similar properties in the same column.
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Why did Mendeleev receive more credit than Meyer?
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Because he published his findings first and left blanks in his table where he knew undiscovered elements would fit such as scandium, gallium, and germanium
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What happened to Mendeleev's table when more elements were found?
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Several elements did not fit anywhere
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How did Henry Moseley arrange the elements and what was the result?
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By atomic number. In result, the misplaced elements fell into place and a clear periodic pattern of elemental properties was found (Periodic Law)
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Periodic Law
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When elements are arranged by increasing atomic number, there is a repitition of chemical and physical properties within a family
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Representative elements
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Groups designated with an A, possess a wide range of chemical and physical properties
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Transition elements
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Groups designated with a B
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What are the three main classifications of the elements?
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1. metals
2. nonmetals 3. metalloids |
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What are the properties of metals?
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-shiny when smooth and clean
-solid at room temperature -good conductors of heat and electricity -malleable, ductile -loose electrons to form s2p6 (cations) |
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Alkali metals
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Group 1A elements
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Alkaline earth metals
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Group 2A elements
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What are the Group B elements (transition elements) divided into?
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1. transition metals
2. inner transition metals |
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What two sets of inner transition metals are located at the bottom of the periodic table?
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Lanthanides and actinides
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What are the properties of nonmetals?
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-usually gases or brittle, dull-looking solids
-poor conductors of heat and electricity -gain electrons to achieve s2p6 |
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Halogens
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-Highly reactive group 7A nonmetals
-Valence configuration s2p5 -Need 1 electron to achieve s2p6 |
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Noble gases
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-Extremely unreactive group 8A nonmetals
-Valence configuration of s2p6 |
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Metalloids
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Elements with physical and chemical properties of both metals and nonmetals
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Label the periodic table
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-Red group: Alkali metals
-Tan group: Alkaline earth metals -Pink elements: Transition metals, "B Elements," D Block -Bottom pink elements: Inner transition metals, "F Block," lanthanides(top) and actinides(bottom) -Yellow group: Halogens -Turquoise group: Noble gases |
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Why do elements in the same group have similar chemical properties?
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Because their atoms have the same number of valence electrons
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All of the elements in group 1A all have a valence configuration of ___.
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s1
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List the metalloids?
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Boron
Silicon Germanium Arsenic Antimony Tellurium Polonium Astatine |
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Describe the properties of Alkali Metals (Group 1A)
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-valence configuration s1
-all silver, soft -react explosively with H2O to form alkaline solution |
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Describe the properties of Alkaline Earth Metals
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-valence configuration s2
-all found naturally in Earth -react with H2O to form alkaline solution |
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What are lanthanides used for?
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CRT's and TV's
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What forms salts?
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Alkali/Alkaline Earth Metals + Halogens
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What makes up the S-Block?
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Groups 1A and 2A
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What makes up the P-Block?
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Groups 3A through 8A
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What makes up the D-Block?
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Transition Metals
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What makes up the F-Block?
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Inner Transition Metals
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What is the atomic radius for metals?
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Half the distance between adjacent nuclei (half the distance across atom)
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What is the atomic radius for nonmetals?
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Half the distance between nuclei of identical atoms that are chemically bonded together (half the distance across bonded atom)
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What pattern is seen in atomic size as you move from left to right across a period? Why?
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Decrease in atomic radius. Because electron shielding increases, positive nuclear charge pulls outermost electrons closer to nucleus.
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What pattern is seen in atomic size as move down a group? Why?
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Increase in atomic radius. Because the atom becomes bigger due to more energy levels. This creates more electrons and these electrons shield outer electrons from pull of nucleus.
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Ion
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An atom or group of atoms that has a positive or negative charge due to the gaining or losing of electrons
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When atoms lose electrons and form positively charged ions, what happens?
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Atomic radius becomes smaller
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Why do atoms become smaller when they lose electrons and form positively charged ions?
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1. Valence electron leaves, leaving outer orbital empty, causes smaller radius
2. Less electrons so shielding decreases, outer electrons are pulled closer to nucleus, causes smaller radius |
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When atoms gain electrons and form negatively charged ions, what happens?
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Atomic radius becomes larger
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Why do atoms become larger when they gain electrons and form positively charged ions?
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Because this increases the electrostatic repulsion between the atoms outer electrons, forcing them to move farther apart, causes larger radius
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