CHEM 5013CHEM 5013

Applied Chemical Applied Chemical PrinciplesPrinciplesChapter TwoChapter Two

Professor BensleyProfessor BensleyAlfred State CollegeAlfred State College

Chapter ObjectivesChapter Objectives

Define the terms Define the terms atom, molecule, atom, molecule, isotope, ion isotope, ion and and functional groupfunctional group in in your own words.your own words.

Describe the nuclear model for the Describe the nuclear model for the atom and identify the numbers of atom and identify the numbers of protons, electrons, and neutrons in a protons, electrons, and neutrons in a particular isotope from its chemical particular isotope from its chemical symbol.symbol.

Chapter ObjectivesChapter Objectives

Calculate the atomic mass of an Calculate the atomic mass of an element from the masses and element from the masses and abundances of its isotopes.abundances of its isotopes.

Determine the number of atoms in a Determine the number of atoms in a molecule from its chemical formula.molecule from its chemical formula.

Describe the arrangement of Describe the arrangement of elements in the periodic table and elements in the periodic table and explain the usefulness of the table.explain the usefulness of the table.

Chapter ObjectivesChapter Objectives Understand the basic differences Understand the basic differences

between organic and inorganic between organic and inorganic chemistry.chemistry.

Use standard chemical nomenclature Use standard chemical nomenclature to deduce the names of simple to deduce the names of simple inorganic compounds from their inorganic compounds from their formulas or formulas or vice versavice versa..

ReviewReview

What is an What is an element?

What is an atom?

What is a compound?

Atomic Structure of MatterAtomic Structure of Matter

Matter is composed of:Matter is composed of:

Parts of the Atom:Parts of the Atom:1.1.

2.2.

““Nuclear Structure” of the Nuclear Structure” of the AtomAtom

Protons

Neutrons

Real Nuclear Structure Real Nuclear Structure of the Atomof the Atom

Electrons are Electrons are depicted as depicted as clouds of negative clouds of negative charge charge surrounding the surrounding the nucleus. nucleus.

Nuclear Structure of the Nuclear Structure of the AtomAtom

Atomic Number (Z):(Z):

Nuclear Structure of the Nuclear Structure of the AtomAtom

Mass number (A): (A):

++ = =

Number of + number of = MassNumber of + number of = Mass ProtonsProtons neutrons neutrons Number Number

Atomic Number and Mass Atomic Number and Mass NumberNumber

Atomic Mass Units (amu)Atomic Mass Units (amu) 1 amu =1 amu = Protons and neutrons nearly Protons and neutrons nearly

times more massive than electronstimes more massive than electrons Proton =Proton = Neutron =Neutron = Electron =Electron =

Nuclear Structure of the Nuclear Structure of the AtomAtom

ProtonProton NeutronNeutron ElectronElectron

SymbolSymbol

LocationLocation

ChargeCharge

MassMass

IsotopesIsotopes

Isotopes:Isotopes:

Isotopic abundance:Isotopic abundance:

IsotopesIsotopes

Mass spectrometers can measure Mass spectrometers can measure the mass of atoms and isotopes.the mass of atoms and isotopes.

IsotopesIsotopes

Mass spectrum for carbon isotopes.Mass spectrum for carbon isotopes.

Atomic SymbolsAtomic Symbols

We use We use atomic symbols to represent to represent atoms of the different elements.atoms of the different elements.

Usually one or two lettersUsually one or two letters If two letters, If two letters, Capital followed by Capital followed by

lowercaselowercase Examples:Examples:

Atomic SymbolsAtomic Symbols Atomic Symbol (Nuclide Symbol)Atomic Symbol (Nuclide Symbol)

ZAE

Example:Example: Chlorine exists as two isotopes: Chlorine exists as two isotopes: chlorine-chlorine-

3535 and and chlorine-37chlorine-37 Written as:Written as:

What is the difference between chlorine-What is the difference between chlorine-35 and chlorine-37?35 and chlorine-37?

Atomic SymbolsAtomic Symbols

Atomic MassesAtomic Masses

Atomic MassesAtomic Masses Fractional Abundance:Fractional Abundance:

Relative atomic mass:Relative atomic mass:

Carbon-12 =Carbon-12 = Carbon-13 =Carbon-13 = Weighted average mass =Weighted average mass =

Atomic MassesAtomic MassesCalculate the atomic mass of boron, B, from Calculate the atomic mass of boron, B, from

the following data:the following data:

ISOTOPE ISOTOPIC MASS (amu) FRACTIONAL ISOTOPE ISOTOPIC MASS (amu) FRACTIONAL ABUNDANCEABUNDANCE

B-10 10.013B-10 10.013 0.1978 0.1978B-11 B-11 11.009 0.8022 11.009 0.8022

Periodic Table of the Periodic Table of the ElementsElements

1869 – Dmitri Mendeleev1869 – Dmitri Mendeleev Found that when elements were Found that when elements were

arranged in order of atomic weight, arranged in order of atomic weight, they could be placed in horizontal they could be placed in horizontal rows, one row under the other, so rows, one row under the other, so that the elements in vertical columns that the elements in vertical columns have similar properties!have similar properties!

Periodic Table of the Periodic Table of the ElementsElements

 

PeriodsPeriods

Referred to by numerical designationsReferred to by numerical designations Top row is period 1, etc.Top row is period 1, etc. The two rows that normally appear The two rows that normally appear

separately at the bottom of the chart separately at the bottom of the chart actually belong within the body of the chart actually belong within the body of the chart in periods 6 and 7.in periods 6 and 7.

GroupsGroups

Each group is identified by a numerical Each group is identified by a numerical designation. Over the years, two designation. Over the years, two different numbering systems have been different numbering systems have been developed. developed.

Group (Family) Names

Periodic Table of the Periodic Table of the ElementsElements

Do you see the heavy staircase in Do you see the heavy staircase in the periodic table?the periodic table?

IonsIons

Ions:Ions:

What is the charge on an electron?What is the charge on an electron? So what happens to the net charge if So what happens to the net charge if

you take one electron away? Add you take one electron away? Add one on?one on?

Ionic SubstancesIonic Substances

Two possibilities for formation of Two possibilities for formation of ions:ions:1.1. Add an electronAdd an electron

2. Lose an electron

IonsIons

IonsIons

Two fundamental ideas about electric Two fundamental ideas about electric charge.charge.1.1.

2.2.

Ionic BondingIonic Bonding

Two depictions of a NaCl crystal.Two depictions of a NaCl crystal.

Chemical FormulasChemical Formulas

Chemical formula::

Convey relative proportions of atoms Convey relative proportions of atoms of the different elements in the of the different elements in the substance.substance.

Examples:Examples:

Molecular FormulasMolecular Formulas

Two types of Chemical Two types of Chemical Formulas:Formulas:1.1. Molecular FormulasMolecular Formulas

2.2. Ionic FormulasIonic Formulas

Ionic FormulasIonic Formulas

Ionic formula:

What is the overall charge on an ionic compound?

Ionic FormulasIonic Formulas

What is the formula of magnesium nitride, What is the formula of magnesium nitride, which is composed of the ions Mgwhich is composed of the ions Mg2+2+ and N and N3-3-??

What is the formula of calcium phosphate What is the formula of calcium phosphate which is composed of the ions Ca which is composed of the ions Ca 2+2+ and and (PO(PO44))3-3-? ?

What is the formula of magnesium oxide What is the formula of magnesium oxide which is composed of the ions Mgwhich is composed of the ions Mg2+2+ and O and O2-2-??