The Periodic Table By Leonard Calvin EdS

How was the Periodic Table created? Science is the search for patterns in nature. In the 1800’s, many scientists noticed patterns in the properties of different elements.

Look at the following elements, what patterns do you notice? ElementAtomic #Atomic RadiusIonization H He Li Be B C N Na Mg Al Si P

Who discovered the patterns? Dimitri Mendeleev Introduced a chart summarizing the known properties of the elements to his students. The chart resembles a calendar.

What did the original Periodic Table look like? Arranged the original 60 elements in order by their increasing masses. Left blanks because he predicted there were missing elements.

Ponder this: Was the great organization of the periodic table invented by humans or discovered by humans? Explain.

What does the modern periodic table look like?

How is the PTE arranged? by the type of element (substance) by the state of the element (solid, liquid, or gas). the mass of the element.

How is the PTE organized? GROUPS  Vertical columns  Similar properties among the elements  Have the same # of electrons in outer shell (valence electrons)  Group 1-used in the making of soaps  Group 2-fire resistant  Group 11-precious metals  Group 17-tendency to form salts  Group 18-unreactive gases

More on how the PT is organized: PERIODS  Horizontal rows  Same number of energy shells (where the electrons are) Example: Period 2 Li Be B C N O F and Ne All have 2 energy shells

Quick Review! The PTE is an arrangement of the __________. The elements are arranged in increasing _________& ___________. The PTE has columns called________. The PTE has rows called___________.

More review! Groups Vertical ________on the PTE. Have __________ properties because of the same number of __________ in the outer shell. Those are called v_______ electrons Periods Horizontal _______ on the PTE. All elements in the same row have the same # of e______ s______.

What’s in the rectangles? Atomic Number-the number of electrons or protons Symbol Name Atomic mass-protons plus neutrons

Practice reading the Periodic Table: What is the atomic number? 8 What is the symbol? O What is the name of the element? oxygen What is the atomic mass? 15.99

Practice reading the Periodic Table? What is the atomic number? 79 What is the symbol? Au What is the name of the element? gold What is the atomic mass?

Practice finding the # of electrons, protons and neutrons. How many protons? 11 How many electrons? 11 How many neutrons?

Practice finding the # of electrons, protons and neutrons. How many protons? 8 How many electrons? 8 How many neutrons?

Practice finding the # of electrons, protons and neutrons. How many protons? 79 How many electrons? 79 How many neutrons?

How do you use the Periodic Table? From the information on the periodic table, we can find the number of electrons, protons and neutrons. Atomic number equals the protons or electrons. Atomic mass minus the atomic number equals the number of neutrons.

Another way the periodic table is organized: Metals Non-Metals Metalloids

Metals 85% of known elements Shiny Opaque Good conductors of electricity Good conductors of heat Malleable-can be molded Ductile-can be drawn into wires All but a few are solid at room temperature (ex: Mercury) Located to the left of zig zag Neodymium

Non-Metals On the right side of the zig zag line. Dull Non-conductors of heat & electricity Brittle, will shatter when hammered At room temperature some are solid, some are liquid, some are a gas Reactive solids Carbon

Metalloids Between metals and non-metals, along zig zag line Weak conductors of heat and electricity Used for semi conductors (conducts w/ higher temps) Take on the properties of their group If closer to the metals- have more metal properties If closer to non-metals- take on those properties Germanium Boron

Metal, non-metal or metalloid? Leah has an element that is silvery gray, solid, brittle and is a semi conductor. What is it?

Metal, non-metal or metalloid? Tommy has an element that is shiny, solid, can be pulled into wire(ductile) and is a good conductor of heat and electricity. What is it?

Metal, non-metal or metalloid? Michael has an element that is a yellow solid that crumbles and does not conduct heat or electricity. What is it?