Atomic Structure Chapter 4. The Atom The smallest particle of an element that retains its identity in a chemical reaction A penny is about 200,000,000.

Atomic Atomic StructureStructure

Chapter 4Chapter 4

The AtomThe Atom

The smallest particle of an The smallest particle of an element that retains its identity in element that retains its identity in a chemical reactiona chemical reaction

A penny is about 200,000,000 A penny is about 200,000,000 copper atoms acrosscopper atoms across

Just How Small Is an Atom?Just How Small Is an Atom? Remember looking at these last Remember looking at these last

year?year? You would have to magnify them a You would have to magnify them a

billion times more to see the atoms billion times more to see the atoms they are made of.(1,000,000,000x)they are made of.(1,000,000,000x)

The AtomThe Atom There are three kinds of particles There are three kinds of particles

that make up atoms.that make up atoms. These are called subatomic These are called subatomic

particles.particles.

Protons & NeutronsProtons & Neutrons

Proton (pProton (p++) is positively charged) is positively charged Neutron (nNeutron (n00) has no charge) has no charge Both have the same mass Both have the same mass

(1.67 x 10(1.67 x 10-24-24g or 1 amu)g or 1 amu)

ElectronsElectrons

Electron (eElectron (e--) is negatively charged) is negatively charged Much less mass than protons or Much less mass than protons or

neutrons (about 2000x less or 0 amu)neutrons (about 2000x less or 0 amu) Are the cause for Are the cause for allall of an element’s or of an element’s or

compound’s behaviorcompound’s behavior

ArrangementArrangement At the center of an atom is the nucleus. At the center of an atom is the nucleus.

Here are the atom’s protons and neutrons. Here are the atom’s protons and neutrons. Almost all of the atom’s mass.Almost all of the atom’s mass.

Electrons are spread outside of and Electrons are spread outside of and around the nucleus. They produce almost around the nucleus. They produce almost all of an atom’s volume (size)all of an atom’s volume (size)

How Do You Tell Them How Do You Tell Them Apart?Apart?

Elements are different because Elements are different because they have different #’s of they have different #’s of protons.protons.

The # of protons is also an The # of protons is also an element’s element’s Atomic NumberAtomic Number..

Mass NumberMass Number

The sum of the protons and the neutrons The sum of the protons and the neutrons in an atom.in an atom.

Can be used to find the number of Can be used to find the number of neutrons an atom has.neutrons an atom has.

(Mass #) = (# of neutrons) + (Atomic #)(Mass #) = (# of neutrons) + (Atomic #)

IsotopesIsotopes

Atoms that have the same number Atoms that have the same number of protons (they have to) and of protons (they have to) and electrons, but different numbers of electrons, but different numbers of neutrons.neutrons.

When atoms begin to have more When atoms begin to have more than enough neutrons, they become than enough neutrons, they become unstable. This is radioactivity.unstable. This is radioactivity.

Starting on p. 91-102Starting on p. 91-102 What year or time period…What year or time period… What country the person was What country the person was

from or where they did their from or where they did their work….work….

What their contribution or What their contribution or discovery was….discovery was….

Why it’s significant……Why it’s significant……

DemocritusDemocritus

John DaltonJohn Dalton

Michael FaradayMichael Faraday

Benjamin FranklinBenjamin Franklin

J.J. ThomsonJ.J. Thomson

Robert MillikanRobert Millikan

Henri BecquerelHenri Becquerel

Pierre and Marie CuriePierre and Marie Curie

Ernest RutherfordErnest Rutherford

Are These the Only Are These the Only People?People?NO !!!NO !!! James Chadwick-discovers the neutron in 1932James Chadwick-discovers the neutron in 1932 Neils Bohr-a GIANT in the field of scienceNeils Bohr-a GIANT in the field of science Albert Einstein-perhaps you’ve heard of himAlbert Einstein-perhaps you’ve heard of him Werner Heisenberg-quantum theoryWerner Heisenberg-quantum theory Joseph PriestleyJoseph Priestley ……and many moreand many more

1 2 3 4

5 6 7 8

Ions (charged particles)Ions (charged particles) Monatomic (1 atom) ions have Monatomic (1 atom) ions have

different numbers of protons and different numbers of protons and electrons.electrons.

An atom has no charge because An atom has no charge because (# of p (# of p++) = (# of e) = (# of e--))

An ion has a charge because there An ion has a charge because there is a charge imbalance is a charge imbalance (# of p(# of p++) ) ≠ (# of e≠ (# of e--))

Charge = (# of pCharge = (# of p++) – (# of e) – (# of e--))

Ions (charged particles)Ions (charged particles) Monatomic (1 atom) ions Monatomic (1 atom) ions have different have different

numbers of protons and electrons. For numbers of protons and electrons. For example: Hexample: H++, Cl, Cl--, Na, Na++, O, O2-2-..

Polyatomic ions (more than 1 atom) Polyatomic ions (more than 1 atom) are small molecules that possess an are small molecules that possess an excess of electrons, so they have a excess of electrons, so they have a charge. For example: NHcharge. For example: NH44

++, PO, PO443-3-, SO, SO44

2-2-, ,

OHOH--..

Ionic CompoundsIonic Compounds Formed from the combining of ions.Formed from the combining of ions. ALWAYS a metal bonded to a non-ALWAYS a metal bonded to a non-

metal.metal. Positive ion is a Positive ion is a cationcation.. Negative ion is an Negative ion is an anionanion.. We will be working with BINARY We will be working with BINARY

compounds (two parts).compounds (two parts).

Naming Ionic CompoundsNaming Ionic Compounds

Cation is always written first.Cation is always written first. Identify the cation and name it.Identify the cation and name it. Identify the anion and name it.Identify the anion and name it.

Formulas of Ionic Formulas of Ionic CompoundsCompounds

Identify the cation and the anion.Identify the cation and the anion. Balance the charges. You need equal Balance the charges. You need equal

amounts of + and – charge. (Criss-cross)amounts of + and – charge. (Criss-cross) Write the formula, with a subscript for Write the formula, with a subscript for

any ion that there is 2 or more of.any ion that there is 2 or more of. If you use 2 or more of a polyatomic ion, If you use 2 or more of a polyatomic ion,

it needs parentheses.it needs parentheses.

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures

Ionic CompoundsMetals

Non-Metals

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures

Ionic Compounds

Hydrates

Metals

Non-Metals

HydratesHydrates

Ionic compounds with water Ionic compounds with water trapped in the crystal structure.trapped in the crystal structure.

Naming HydratesNaming Hydrates

Name the ionic part of the Name the ionic part of the compound first.compound first.

Then name the hydrate part with Then name the hydrate part with a prefix and the word “hydrate”.a prefix and the word “hydrate”.

What are the prefixes????What are the prefixes????

PrefixesPrefixes 1------mono1------mono 2------di2------di 3------tri3------tri 4------tetra4------tetra 5------penta5------penta 6------hexa6------hexa 7------hepta7------hepta 8------octa8------octa 9------nona9------nona 10----deca10----deca

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures

Ionic Compounds

Hydrates

Metals

Non-Metals

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures

Ionic Compounds

Hydrates

Covalent Compounds

Metals

Non-Metals

Covalent CompoundsCovalent Compounds

ALWAYS a nonmetal bonded to ALWAYS a nonmetal bonded to a nonmetala nonmetal

Not bonded due to opposite Not bonded due to opposite electrical charges (like ionic electrical charges (like ionic compounds are)compounds are)

Naming Covalent Naming Covalent CompoundsCompounds

Name the cation as an Name the cation as an elementelement.. Add a prefix to the cation if there Add a prefix to the cation if there

are two or more.are two or more. Name anion as an Name anion as an ionion Add a prefix to the anion no Add a prefix to the anion no

matter how many there are.matter how many there are.

Formulas for MoleculesFormulas for Molecules

The prefix in each part of the The prefix in each part of the name tells you how many of name tells you how many of component there are/is.component there are/is.

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Mixtures Heterogeneous Mixtures

Ionic Compounds

Hydrates

Covalent Compounds

Acids

Metals

Non-Metals

AcidsAcids The cation for an acid is ALWAYS hydrogen.The cation for an acid is ALWAYS hydrogen. The names for acids come from the anion in the The names for acids come from the anion in the

acid.acid. The names for acids are as shown:The names for acids are as shown:

HCl-Hydrochloric AcidHCl-Hydrochloric Acid HNOHNO33-Nitric Acid-Nitric Acid

HH22SOSO44-Sulfuric Acid-Sulfuric Acid

HH33POPO44-Phosphoric Acid-Phosphoric Acid

HCHHCH33COO-Acetic AcidCOO-Acetic Acid

1st Element Listed

Metal Hydrogen Nonmetal

Ionic-no prefixes Acid-memorized Molecular-prefixes