Transcript CHAPTER 5 NOMENCLATURE

Unit 2
Chapters 5 and 6
Atoms/Periodic Table/
NOMENCLATURE
NAMING AND FORMING
COMPOUNDS
Review of Atomic
Structure
• What is an atom?
– The smallest particle of an element that
retains the properties of that element.
• What are protons?
– Positively charged particle in the
nucleus of an atom.
• What are neutrons?
– Neutral particles in the nucleus of an
atom.
Atoms…
• What are electrons?
– Negatively charged particles that orbit around
the nucleus in certain energy levels.
• What is the nucleus?
– The center of an atom where the protons and
neutrons are. It is what gives the atom its
mass.
• What are energy levels (orbitals)?
– Certain areas around the nucleus where
electrons are found moving. They exist in
certain energy levels.
Atoms…
• What are isotopes?
– Atoms of the same element that differ
by the number of NEUTRONS
Define...
• Atomic Number
– the number of
protons inside
the nucleus of an
atom.
– It gives that
atom it’s
identity.
• Mass Number
– the weight of
the nucleus an
atom.
– It is the protons
and neutrons
added together.
– It is measured in
units called
AMUs (atomic
mass units)
Models of Atoms
• Draw a Model of a helium-4 atom
• Draw a model of a Calcium-40 atom
• Review Questions Together
THE PERIODIC TABLE
• AN ARRANGEMENT OF THE
ELEMENTS IN ROWS AND
COLUMNS ACCORDING TO
SIMILARITIES IN THEIR
PROPERTIES.
• THEY ARE ARRANGED ACCORDING
TO INCREASING NUMBER OF
PROTONS (ATOMIC NUMBER).
WHAT ARE GROUPS?
• COLUMNS OF ELEMENTS AND ARE
GIVEN NUMBERS AND A LETTER
OF “A” OR “B”.
• GROUP A
– Are located in the TALL columns to
either side of the periodic table.
– They are known as the
REPRESENTATIVE elements.
Groups Continued…
• GROUP B
– Are located in the center of the
periodic table. They are the short
columns in the middle.
– They are known as the TRANSITION
elements.
WHAT ARE PERIODS?
– ARE THE ROWS IN THE
PERIODIC TABLE.
– THERE ARE 7 PERIODS IN THE
PERIODIC TABLE.
• NUMBER THEM ON YOUR
TABLE.
WHERE ARE THE METALS
AND NONMETALS?
• DRAW A LINE ON YOUR TABLE
THAT SEPARATES THE METALS
AND NONMETALS.
3 General Categories Have
Distinguishing Properties
• METALS HAVE HIGH LUSTER
WHEN CLEAN AND A HIGH
ELECTRICAL CONDUCTIVITY.
• NONMETALS ARE NONLUSTROUS
AND ARE POOR CONDUCTORS.
WHAT ARE SEMIMETALS
OR METALLOIDS?
• ELEMENTS WITH THE
PROPERTIES OF BOTH METALS
AND NONMETALS.
• SHADE THE METALLOIDS ON
YOUR PERIODIC TABLE.
Naming Certain Groups:
• Group 1A are known as the alkali
metals.
• Group 2A are known as the alkaline
earth metals
• Group 7A are known as the halogens.
• Group 8A are known as the Noble
Gases, or the Inert Gases. (they have
filled outermost energy levels and
don’t like to react)
The Inner Transition Metals (also
called the rare earth elements.)
• Located at the bottom of the
Periodic Table – bottom 2 rows.
• The two rows are called the
Lanthanide and Actinide Series
because they are named after the
elements that start their rows:
Lanthanum and Actinium.
– They belong to period 6 and 7
respectively.
What category do most
elements belong to?
• 80% of the elements are metals. All
metals are solids at room
temperature with one exception.
• What is it?
– Mercury, Hg, is liquid at room
temperature
• Review:
Nomenclature:
IONS and IONIC
COMPOUNDS
• ION - Charged atoms (lost or gained
electrons)
• Cations - are positive ions, they have
lost electrons
• Anions - are negative ions, they have
gained electrons.
• Model how sodium and chlorine atoms
form ions.
Ionic Compounds Cont…
• Show Magnesium atom forming
magnesium ion
• Draw a compound between magnesium
and chlorine
Naming
• How do we name positive ions?
– Simply say the name of the element with
the word ion after it.
• How do we name negative ions?
– Change the last part of the element’s
name to end with –IDE
• Chlorine becomes Chloride
• Sulfur become Sulfide
Physical Properties of
IONIC COMPOUNDS
• CALLED A FORMULA UNIT.
• MADE UP OF IONS. A POSITIVE
HOOKED TO A NEGATIVE. THEIR
CHARGE MUST ADD TO ZERO.
• METAL ION (+) HOOKED TO
NONMETAL (-).
• ARE SOLIDS AT ROOM TEMP.
• HAVE HIGH MELTING POINTS.
Review
• Problems in notepack
Periodic Table
• There is a pattern in predicting how
many electrons are lost and gained
for the REPRESENTATIVE
ELEMENTS.
• Write these charges onto your
periodic table with me now.
MOLECULAR
COMPOUNDS
• MOLECULES ARE THE SMALLEST
ELECTRICALLY NEUTRAL UNIT OF
A SUBSTANCE THAT STILL HAS
THE PROPERTIES OF THE
SUBSTANCE.
• MOLECULES ARE MADE UP OF
TWO OR MORE NONMETALS THAT
ACT AS A UNIT.
More on Molecules
• MOLECULES ARE MADE UP OF
NONMETALS SHARING
ELECTRONS.
• This is called a COVALENT BOND
• Draw a model of a hydrogen molecule
– Water
– Carbon dioxide
Physical Properties that
Molecules Share:
• THEY CAN BE A SOLID, LIQUID,
OR A GAS AT ROOM
TEMPERATURE.
• HAVE LOW MELTING POINTS.
REVIEW!!
MOLECULES VS
FORMULA UNITS
• MOLECULE - A GROUP OF NEUTRAL
ATOMS THAT ACT AS A UNIT.
– TWO OR MORE NONMETALS
COVALENTLY BONDED. ELECTRON
SHARING.
• FORMULA UNIT- COMPOSED OF A
CATION WITH AN ANION.
– METAL (+) WITH A NONMETAL(-).
– IONIC BOND ELECTRON TRANSFER.
CHEMICAL FORMULAS
• SHOWS THE KINDS AND
NUMBERS OF ATOMS IN THE
SMALLEST REPRESENTATIVE
UNIT OF THE SUBSTANCE.
• Monatomic elements are represented
by their Symbols.
7 Naturally Occurring
Diatomic Molecules
• There are 7 naturally occurring diatomic
elements. Write them down and star them
on your periodic tables...
• H2
F2
• O2
Cl2
• N2
Br2
I2
Formulas
• Molecular Formulas shows the kinds and
numbers of atoms
present in a molecule
of a compound.
• We cannot determine
the shape or
geometry.
• CO2 – has 1 carbon
atom and 2 oxygen
atoms. We don’t know
how connected.
• Formula Units The lowest whole
number ratio of
ions in a compound.
• Formula Units form
repeating threedimensional
crystals.
How can we name the ions of
transition metals (including tin
and lead?
• Since these elements have more than
one common charge, we must tell the
reader how many electrons were lost
when forming the compound.
• We use ROMAN NUMERALS to
indicate how many electrons were
lost.
• Copper (II) ion - lost two electrons
• Tin (IV) ion - lost 4 electrons