Warm - UpWe breath oxygen in the air and we live.

In water, we drown. But wait – water is H2O – by mass nearly 90% oxygen, with the rest hydrogen. So why can’t we breathe water?

– The oxygen in the air is a molecule. But the oxygen in water is chemically bonded to hydrogen. Even fish cannot breathe the oxygen in H2O.

3-6 Modern Period Table• Describe the arrangement of elements in

the modern periodic table.

• Identify general properties of metals, metalloids, and non-metals.

• Describe how properties of elements change across a period in the periodic table.

Classes of element• Metals

– Most elements found in nature are metals– Blue boxes on textbook table.– Good conductors of heat and electricity.– Shiny when smooth (lustrous).– High melting points, solid at room temp.

• except mercury.

– Malleable – • hammered without shattering / into thin sheets

– Ductile • drawn into thin wire.

– Most react with oxygen.

Classes of elements• Non metals

– Orange boxed elements.– Generally have properties opposite of metals. – Non-conductive of heat or electricity.– Dull

• non shiny.

– Brittle • shatter when struck.

– Low melting points • most are gas at room temp.

– Reactivity varies by the nonmetal elements.

Classes of elements• Metalloids

– Elements that have properties that fall between the metals and nonmetals.

– Metalloids conductivity of electricity varies with temperature.

– Silicon (Si) and Germanium (Ge) are good insulators at low temperatures, but they are good conductors at high temperatures.

The Periodic Law• Groups – Columns

that increase atomic number.– Also called families.– Number 1A – 8A or

1-18– Main elements are

1, 2 & 13 – 18.– Similar chemical properties.– Lithium, Sodium, and Potassium have 1 V.E.– Groups have similar electron configurations.

Classes of Elements• Solid elements have black

symbols

• Liquid elements have blue or purple

• Gaseous elements have red.

• Metals have blue background.

• Metalloids have a green background.

• Nonmetals have an orange background.

Variation across period• Atomic number increases across period.

• Atoms become less and less metallic.

• Metals reactivity decreases.– Sodium reacts with water instantly, but

magnesium must have hot water to react.

• Nonmetals reactivity increases.

3-6 Summary• How are the element arranged in the

Periodic table?– Increasing atomic number.

• What is a row called?– periods

• What is a column called?– Family or group

• How do properties repeat?– Repeat row to row

8-2 Summary • What are the three classes of elements?

– Metal, metalloid, nonmetal

• What are the properties of metals?– Shiny when smooth, malleable, ductile,

conductive, solid at room temp. (High M.P.)

• What are the properties of nonmetals?– Dull, brittle, non conductive, most gasses at

R.T ( low M.P.)

• What are the properties of metalloids?– Properties in between metals and nonmetals.