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Atomic Number
• This refers to how many protons an atom of that element has.
• No two elements, have the same number of protons.
Bohr Model of Hydrogen Atom
Wave Model
Atomic Mass
• Atomic Mass refers to the “weight” of the atom.
• It is derived at by adding the number of protons with the number of neutrons.
HThis is a helium atom. Its atomic mass is 4 (protons plus neutrons).
What is its atomic number?
• The arrangement of elements in vertical column called Groups and horizontal rows called Periods in order of increasing proton number
• There are 18 Groups numbered 1-18 and 7 Periods numbered 1-7 in a Periodic Table.
MODERN PERIODIC TABLE
Periods
• Across the period from left to right
Proton number increasesElement become non-metallic
Sodium and water
https://www.youtube.com/watch?v=uqDWbknpiVk
Potassium and water https://www.youtube.com/watch?v=OFG4Yr7lQzw
Alkali Earth Metals
Alkaline Earth Metals
• 2nd Family • From Beryllium to Radium • Shiny, silvery-white• Somewhat reactive
Elements In Family
• Beryllium• Magnesium• Calcium• Strontium• Barium• Radium• Unbinilium
Representative Elements
and has a higher melting point than the alkali metal in the same period.
• Each alkaline earth metal is denser and harder
Alkaline Earth Metals• Next to the alkali metals are the alkaline
earth metals.
• Alkaline earth metals are reactive, but not as reactive as the alkali metals.
Group Trends
• silvery and of fairly low density• density increases down the group
Group Trends
– stronger metallic bonding than the alkali metals
• also harder and have higher melting points
Element Melting Point (°C) Hatm (kJ/mol)
Mg 649 149Ca 839 177Sr 768 164Ba 727 175
General Properties
They are metalsThey are good conductors of heat and electricityTheir compounds are all white or colourlessIn all compounds they have an oxidation number
of +2They are called alkaline earth metals because
their oxides and hydroxides are basicThey react with acids to produce hydrogen
Uses
• Beryllium is used in nuclear applications• http://www.periodicvideos.com/nyt/videos/0
04.htm
Radium is used to treat cancer• Calcium is necessary for strong bones
TRANSITION METALSGroups in the middle
Good conductors of heat and electricity.
Some are used for jewelry.The transition metals are
able to put up to 32 electrons in their second to last shell.
Can bond with many elements in a variety of shapes.
Where are the transition metals?The transition metals are the block of elements located between group 2 and group 3 of the periodic table.
Ac Rf Db Sg Bh Hs Mt Ds Rg
La Hf Ta W Re Os Ir Pt Au Hg
Y Zr Nb Mo Tc Ru Rh Pd Ag Cd
Sc Ti V Cr Mn Fe Co Ni Cu Zn
?
Here, the word ‘transition’ is used to mean ‘in-between’.
group 2 group 3
Why are they called the ‘typical metals’?
There are over 30 transition metals.
The transition metals are known as ‘typical’ metals. Why do you think this might be?
They include most of the metals we are familiar with and use everyday, such as iron, copper and gold.
However, there are many transition metals that are less familiar to us, because they are very rare or have few uses.
The transition metals are known as ‘typical’ metals because of their physical properties. They are:
What are the properties of the transition metals?
lustrous (bright and shiny).
high density.
good conductors of heat and electricity.
high melting and boiling points (except mercury, which is liquid at room temperature).
hard and strong.
malleable (can be bent and pressed into different shapes) and ductile (can be drawn into wires).
Comparing properties of different metals
How do the properties of transition metals compare with those of alkali metals?
are more dense. This means that in a fixed volume of metal there are more atoms of a transition metal than there are of an alkali metal.
have higher melting and boiling points – except mercury.
are harder and stronger. They cannot be cut with a knife.
Compared to the alkali metals, the transition metals:
Transition metal compounds and colour
Most transition metals form coloured compounds.
Copper (II) sulfate crystals (CuSO4.H2O) is blue – these can be turned white by heating the crystals to remove the water.
Iron (III) oxide (Fe2O3) is red/brown – when hydrated this is rust.
Iron (II) oxide (FeO2) is black.For example:
http://chemistry.about.com/video/Properties-of-Transition-Metals.htm
Groups 13 through 18
Representative Elements
• The elements in Groups 13-18 are not all solid metals like the elements of Groups 1 and 2. Infact, a single group can contain metals, nonmetals, and metalloids and have members that are solids, liquids, and gases.
Group 13, the Boron Family
BORON FAMILY
Group 3• 3 electrons in
the outer shell• Most are
metals• Boron is a
metalloid
Boron Family
• boron family -- Group 13.• This group includes the elements boron,
aluminum, gallium, indium, and thallium. • The atomic number is 5• The atomic symbol B• Melting point= 2,076◦C• Boiling point= 3,927◦C
http://www.worldofteaching.com/powerpoints/chemistry/group%2013.ppt#256,1,Group 13, the Boron Family
Group 13—The Boron Family• The elements in Group
13 are all metals except boron, which is a brittle, black metalloid.
• Without using boron in cookware the products when transferred from a heat place to a non-heated place will cause the item to crack. So using boron helps.
How does boron effect our lives?
Boron Water Solution• Baron Water Solutions'
equipment will give you soft water, which will take away spots from your dishes and hard water build-up on your faucets and appliances, which in turn will add years to your water heater, refrigerator, dishwasher and washing machine.
• Several studies say that lack of boron weakens bones, but there is no data to show that extra boron makes bones stronger. Also boron is are used in pills to help increase blood levels for post- menopausal woman.
Group 13—The Boron Family
Representative Elements
• Aluminum is used to make soft-drink cans, cookware, siding for homes, and baseball bats.
• Gallium is a solid metal, but its melting point is so low that it will melt in your hand.
• It is used to make computer chips.
CARBON FAMILY Group 4• 4 electrons in
the outer shell• Contains
metals, metalloids, and a non-metal Carbon (C)
CARBON FAMILY Group 4• 4 electrons in
the outer shell• Contains
metals, metalloids, and a non-metal Carbon (C)
NITROGEN FAMILY Group 5• 5 electrons in
the outer shell• Can share
electrons to form compounds
• Contains metals, metalloids, and non-metals
OXYGEN FAMILY Group 6• 6 electrons in
the outer shell• Contains
metals, metalloids, and non-metals
• Reactive
HalogensGroup 7• 7 electrons in
the outer shell• All are non-
metals• Very reactive
are often bonded with elements from Group 1
Noble GasesGroup 8Exist as gasesNon-metals8 electrons in the outer
shell = FullHelium (He) has only 2
electrons in the outer shell = Full
Not reactive with other elements
Rare Earth MetalsSome are
RadioactiveThe rare
earths are silver, silvery-white, or gray metals.
Conduct electricity