Organization of The Periodic Table Open Chemical Building

Organization of The Periodic Table Open Chemical Building Blocks Book to Page 85. Get chalkboards, chalk, and eraser

Nucleus • Center of the atom. • Makes majority of the atom’s mass. • Made of Protons and Neutrons. Nucleus

Protons • Part of the nucleus • Have positive (+) charge

Neutrons • Part of the nucleus • Have neutral charge

Electrons • Orbit around the nucleus • Have negative (-) charge

Atomic Number • Definition: the number of protons in the nucleus • Tells us the identity of the element. Every element is defined by the number of protons in its nucleus

Isotopes • Atoms with the same number of protons but different numbers on neutrons • Example: Carbon So you can change the number of neutrons and the element still maintains its identity

Questions • 1) What particles make up an atom? • 2) What are the charges on these particles? • 3) What particles make up the nucleus?

Questions • 1) What is Oxygen’s atomic number? • 2) How many protons does Oxygen have? • 3) If I have 4 protons what element am I? • 4) If I have 4 neutrons what element am I?

Reading the Periodic Table Mass

Atomic Mass • Definition: the ~ mass of one atom of an element • Tells us how much one atom weighs in atomic mass units. Mass

Organization of The Periodic Table Group/Family Period Ordered by atomic mass. Columns arranged to form groups with similar properties

Assessment • Which element has the greatest atomic mass? • Lithium • Sodium • Potassium • Rubidium

Reactivity • The ease and speed with which an element combines, or reacts, with other elements or compounds Pure sodium reacts explosively with air

Groups/families of elements have similar reactivity Group 1: metals that react violently with water Group 18: Gases that barely react at all Why do groups/families of elements react the same way?

Atoms have neutral charge • # of Protons (+) = # of Electrons (-) = 0 charge • Example: Hydrogen • How many electrons does C have?

Electrons orbit in “shells” • 1 st shell can fit 2 electrons 1 st period/row • 2 nd and 3 rd shells can fit 8 electrons 2 nd period/row 3 rd period/row

Atoms want their shells to be full • 2 electrons in first shell • 8 electrons in 2 nd and 3 rd shells • Examples:

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?

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 its outer 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?

Only use the 1 st 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 its • outer 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?

Take home message • The properties of an element can be predicted from its location on the Periodic Table • This is largely a result of the number of electrons in their outer shell.

Metals, Metalloids, and Nonmetals

Metals • Shiny • Solids (at room temp) • Malleable – can be hammered flat • Ductile – can be pulled into wire • High Conductivity – ability to transfer heat or electricity to another object

Reactivity of Metals High Low Metals will usually lose electrons when they react with other elements

Nonmetals • Opposite of properties of metals • Not shiny • Poor conductors • Mostly gases (at room temperature) • Solids are brittle Sulfur

Reactivity of Nonmetals Low High Nonmetals will usually gain or share electrons when they react with other elements

Some Important Nonmetals • Carbon – important element for making up living organisms • Noble Gases – group 18 – very nonreactive. Have full outer shells.

Metalloids • Inbetween metals and nonmetals • Solids (at room temp) • brittle and hard • Semiconductors – can conduct electricity under some conditions but not others. – very important for computer chips • Most common example – Silicon – in sand glass

Assessment • • • The atomic number is the number of valence electrons. neutrons. protons in the nucleus. electrons in the nucleus.

Assessment • The periodic table is a chart of the elements that shows the repeating pattern of their • energies. • properties. • element symbols. • names.

Assessment • Which piece of information cannot be found in a square on the periodic table? • Atomic mass. • Chemical symbol. • Atomic number. • Number of neutrons.

Assessment • Which element will have properties most similar to Calcium? • Potassium. • Scandium. • Magnesium. • Bromine.

Assessment • Which group is most likely to lose/share 2 electrons in a chemical reaction? • 1. • 2. • 17. • 18.

Assessment • Which side of the periodic table contains most of the nonmetals? • Left side. • Right side. • Middle.

Assessment • • • Which is not a property of nonmetals? Brittle. Nonmalleable. High conductivity. Most are gases at room temperature

Assessment • Which metal is probably the most reactive? • Potassium • Calcium • Scandium • Titanium

Assessment • Which nonmetal is probably the most reactive? • Nitrogen • Oxygen • Fluorine • Neon