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 reactivityGroup 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 MetalsHigh 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 ironPure copper

Groups 13-15

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

Pure aluminum Pure lead

Lanthanides

• 1st row below the Periodic Table• Soft, malleable, shiny metals• Often mixed with other metals to make

alloys

Pure cerium Pure Samarium

Actinides

• 2nd 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!

Item Type of Metal GroupMom’s wedding ring Gold, Transition Metal 11

Example

Nonmetals• Opposite of properties

of metals• Not shiny• Poor conductors• Mostly gases (at room

temperature)• Solids are brittle

Sulfur

Reactivity of NonmetalsHighLow

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