Transcript Chemical Names and Formula

Chemical Names and
Formula
Chemistry
Cook
Periodic Table
• There are over 90 naturally occurring
elements/atoms and about 25
elements made in the lab.
• Various combinations of atoms can be
formed, and which such diversity we
need a way to name and communicate
these variations
Periodic table
• Elements are arranged in row and
columns on the: Periodic table
• Hydrogen, the smallest and lightest
element in top right corner
• Helium is atomic number 2
Atomic Numbers
• Krypton
Calculate
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For any element:
Number of Protons = Atomic Number
Number of Electrons = Number of Protons = Atomic Number
Number of Neutrons = Mass Number - Atomic Number
For krypton: Number of Protons = Atomic Number = 36
Number of Electrons = Number of Protons = Atomic
Number = 36
• Number of Neutrons = Mass Number - Atomic Number =
84 - 36 = 48
Periodic Table
• A column of elements in the periodic table
is known as a group
– There are 18 groups
– Group 1A:
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H
Li
Na
K
RB
Cs
Breakdown of each group
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Group 1=Alkali Metals
Group 2= Alkaline Earth Metals
Group 3-12= Transition metals
Group 13,14 & 15= Other metals
Metalloids=Boron diagonal down over and down over( A big
L)
Group 14-16 =Non Metals
Group 17= Halogens (salt formers)
Group 18= Noble gases
Rare Earth Metals= Man made elements inserted in the
transition metal at 56 and 88
Chemical Elements.com - Noble Gases
Alkali
Metals/Representative
metals (A)
• The illustrate the entire range of
chemical properties
– Both metals and non metals
– They do not include transition metals or
inner transition metals (man made ones)
Metallic Metals
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A Groups (1, 2 13-18)
Have high luster when cleaned
High electrical conductivity
Ductile
– Can be drawn into wires
• Malleable
– Beaten into sheets (dyes at GM plants)
Groups
• 1A starts with H or Li
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2A
3A
4A
5A
6A
7A
• Hydrogen is special It is a non metal in group 1A
starts with Be
starts with B
starts with C
starts with N
starts with O
starts with F
Transition Metals (B)
• B group elements
• Inner transition metals (rare earth
metals).
Non Metallic
• Elements that are:
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Non lustrous
Poor conductors of electricity
Some are gases
Others are brittle solids and some
liquids at room temperature
Semi Metals or
Metalloids
• Elements with the properties of both
metals and nonmetals
– Silicon
• Found in transistors
– Good semi conductor
– Conducts electricity in a special way
• Breast implants (cheap ones)
Atoms and Ions
• All elements are composed of atoms of the same
kind
– Atomic Theory (review)
– An atom is electrically neutral because it has an equal
number of protons and electrons
• Na atomic number is 11 and has 11 protons and is positively
charged, has 12 neutrons
• Because Neutrons have no charge the total charge of Na is
(+11)+ (11)=0
• When elements form compounds they can gain or lose
electrons, and when the number of electrons is not equal to
the number of protons then the atom becomes a
– Ion
IOns
• Are atoms or groups of atoms that
have a positive or negative charge
• Formed when atoms gain or lose
electrons
Positive ions
• Metals tend to form positive ions by losing
one or more electrons
– Cation
• Any atom or group of atoms with a positive charge
• Na ion is form by the loss of one electron from the
Na atom
• Sodium ion has 11 protons and 10 electrons it has a
charge of 1+
• Atomic charges are written with the number followed
by a sign
– Na1+ or Na+ (always write ions this way)
– If the number is 1 it can be omitted
Ions
• Mg ions are formed differently
because they have different valence
electrons (electrons in outer shell)
• Mg has a charge of 2+ so it has 12
protons, and 10 electrons
Negative Ions
• Nonmetallic elements tend to gain one or
more electrons
• Anions
– Atoms or groups of atoms with a negative
charge
– Anions have more electrons (unlike cations).
– Cl ions has 17 protons and 18 electrons
– It has a charge of -1
– Oxide ion has a charge of -2
Compounds
• Are pure substances the differ from elements
because they contain more than one kind of atom.
• Law Of Definite Proportions: In any chemical
compound the elements are always combined in
the same proportion by mass
• A Molecule is a neutral group of atoms that act as
a unit. All molecules of a given compound are
neutral.
• Compounds that are composed of molecules are
molecular compounds.
Law of Definite
Proportions
• MgS is a compound. IF we have 100g
of this compound
– It will always contain:
• 43.13g of Mg
• 56.87g of S
• This mass ratio will never change no
matter how much you have
Chemical Formulas
• There are more than 4 million chemical
compounds.
• Chemical Formulas
– Some are molecular
– Some are ionic
• A chemical formula shows the number and kinds
of atoms present in a molecule.
• A molecular formula shows the number and kinds
of atoms present in a molecule of a compound
– Example = H2O CO2 C2H6 C2H6O
Formulas and Names of
Common Metals Ions with
more than 1 ionic charge
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Formula Name
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Cu1+
Cu2+
Fe2+
Fe3+
Hg2
Hg2+
Stock Name
Copper (I) Ion
Copper (II) Ion
Iron (II) Ion
Iron (III) Ion
Mercury (I) Ion
Mercury (II) Ion
• Review Table 5-3
Classical Name
Cuprious ion
Cupric Ion
Ferrous Ion
Ferric Ion
Mercurrous Ion
Mercuric Ion
Rules for naming
• Compounds that give OH- ions
• Bases
• Compounds that give H+ ions
• Acids
• ite ending
• Will always indicate less oxygen
• ate ending
• Will always indicate more oxygens
Binary ionic compounds
• Composed of two elements
– Always cation and anion
– They always have ide ending
– Name metal first then put ide ending on
nonmetal
• Sodium chloride
– Monoatomic always have ide ending
Binary Ionic compounds
• Name by writing name of cation
followed by name of anion (ide
ending).
Ternary Ionic Compounds
• Contain 3 different elements
• They usually contain one or more
polyatomic ions
• First write down formulas of ions
• Then balance charges
• An ate or ite ending on polyatomic ion
• Calcium nitrate
Acids
• Are compounds that give off
hydrogen ions when dissolved in
water.
• When anion ends in ide the acid name
begins with prefix hydro. The stem
(nonmetal in most cases ends with ic)
• HCl= hydrochloric acid
rules
Anion ending
Example/Stem
Acid Name
Example
ide
ClChloride
Hydro (stem) ic
acid
Hydrochloric
acid
ite
SO2-3
Sulfite
(stem) ous acid
Sulfurous acid
ate
NO-3
(stem) ic acid
Nitric acid
nitrate