Organization of The Periodic Table Open to page 112 and 113.

Nucleus Center of the atom. Makes majority of the atom’s mass. Made of protons and neutrons.

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 Mass

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

Assignment Read p. 109 – 117 Complete Section 2 Assessment #1-3

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

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

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?

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.

Question How many electrons does an oxygen have?

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

Sodium reacting to water. Magnesium reacting to water.

Alkali Metals Metals in Group 1 Often lose an electron when they react with other elements Most Reactive: Rare to find them in their pure form because they are so reactive Very shiny and soft Example: Lithium batteries Potassium in its pure form

Alkaline Earth Metals Group 2 Hard, gray-white, good conductor of electricity Lose 2 electrons when they react with other elements Hard to find in pure form. Example: Calcium in your teeth and bones. Calcium in its pure form

Transition Metals Groups 3 – 12 Hard, shiny, good conductors of electricity –Can form colorful compounds Less reactive Examples: iron, gold, copper, nickel Pure iron Pure copper

Groups Only some are metals Not very reactive Examples: aluminum, tin, lead Pure aluminum Pure lead

Lanthanides 1 st row below the Periodic Table Soft, malleable, shiny metals Often mixed with other metals to make alloys Pure cerium Pure Samarium

Actinides 2 nd row below the Periodic Table Only the first six naturally occur on Earth The other elements are synthetic and unstable –Some only exists for a few seconds after being made Depleted uranium

Assignment Worksheet “Elements and the Periodic Table”

Assignment Go on a metal scavenger hunt at your house, school, etc… Make a list of 10 metals you find –Identify each metal and the group it belongs to. –You cannot write down the same metal more than twice! ItemType of MetalGroup Mom’s wedding ringGold, Transition Metal11 Example

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

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

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 and 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