11 Atomic Mass Definition: the ~ mass of one atom of an element Tells us how much one atom weighs in atomic mass units.Mass
12 Organization of The Periodic Table Group/FamilyPeriodOrdered by atomic mass. Columns arranged to form groups with similar properties
13 Assessment Which element has the greatest atomic mass? Lithium Sodium PotassiumRubidiumRubidium
14 ReactivityThe ease and speed with which an element combines, or reacts, with other elements or compoundsPure sodium reacts explosivelywith air
15 Groups/families of elements have similar reactivity Group 1: metals that react violently with waterGroup 18: Gases that barely react at allWhy do groups/families of elements react the same way?
16 Atoms have neutral charge # of Protons (+) = # of Electrons (-) = 0 chargeExample: HydrogenHow many electrons does C have?carbon has 6 electrons.
17 Electrons orbit in “shells” 1st shell can fit 2 electrons2nd and 3rd shells can fit 8 electrons1st period/row2nd period/row3rd period/row
18 Atoms want their shells to be full 2 electrons in first shell8 electrons in 2nd and 3rd shellsExamples:
19 Question How many electrons does an oxygen have? How many electrons are in its outer shell?Which group is oxygen most likely to react with?
20 Question For the first 3 periods: 1) How many electrons are in the outer shell of each element in group 1? Group 2?Group 13? Group 14? Group 15? Group 16? Group 17? Group 18?2) How many electrons does each element in each group above need to fill itsouter shell?3) Which groups are the most likely to react with one another?4) Which group is least likely to react with any other group?
21 Only use the 1st 3 periods For the first 3 periods: 1) How many electrons are in the outer shell of each element in group 1? Group 2?Group 13? Group 14? Group 15? Group 16? Group 17? Group 18?2) How many electrons does each element in each group above need to fill itsouter shell?3) Which groups are the most likely to react with one another?4) Which group is least likely to react with any other group?
22 Take home messageThe properties of an element can be predicted from its location on the Periodic TableThis is largely a result of the number of electrons in their outer shell.
24 Metals Shiny Solids (at room temp) Malleable – can be hammered flat Ductile – can be pulled into wireHigh Conductivity – ability to transfer heat or electricity to another object
25 Reactivity of Metals Low High Metals will usually lose electrons when they react with other elements
26 Nonmetals Sulfur Opposite of properties of metals Not shiny Poor conductorsMostly gases (at room temperature)Solids are brittleSulfur
27 Reactivity of Nonmetals LowLowHighNonmetals will usually gain or share electrons when they react with other elements
28 Some Important Nonmetals Carbon – important element for making up living organismsNoble Gases – group 18 – very nonreactive. Have full outer shells.
29 Metalloids Inbetween metals and nonmetals Solids (at room temp) brittle and hardSemiconductors – can conduct electricity under some conditions but not others.very important for computer chipsMost common example – Silicon – in sand and glass
30 Assessment The atomic number is the number of valence electrons. neutrons.protons in the nucleus.electrons in the nucleus.Protons in nucleus
31 AssessmentThe periodic table is a chart of the elements that shows the repeating pattern of theirenergies.properties.element symbols.names.properties
32 AssessmentWhich piece of information cannot be found in a square on the periodic table?Atomic mass.Chemical symbol.Atomic number.Number of neutrons.Number of neutrons
33 Assessment Which element will have properties most similar to Calcium? Potassium.Scandium.Magnesium.Bromine.Magnesium.
34 AssessmentWhich group is most likely to lose/share 2 electrons in a chemical reaction?22.214.171.124.Magnesium.
35 AssessmentWhich side of the periodic table contains most of the nonmetals?Left side.Right side.Middle.Magnesium.
36 Assessment Which is not a property of nonmetals? Brittle. Nonmalleable.High conductivity.Most are gases at room temperatureMagnesium.
37 Assessment Which metal is probably the most reactive? Potassium CalciumScandiumTitaniumPotassium
38 Assessment Which nonmetal is probably the most reactive? Nitrogen OxygenFluorineNeonFlourine