Introduction to Chemistry

• Study of the _______________ of matter and the _______________ matter undergoes.

• 1. Organic chemistry - • 2. Inorganic chemistry -• 3. Analytical chemistry -• 4. Physical chemistry• 5. Biochemistry -

Understanding Concepts

• Chemistry deals with _______________ facts - facts that can be discovered by making observations and doing experiments.

• It is often necessary to rely on information that others have discovered.

Diamond• Hardest known substance.• A form of the element carbon.• Highly ordered molecular

structure.• Not the most stable form of

carbon.

Macro vs. Micro

• _______________ - things you see with the unaided eye or large scale experimenting.

• _______________ - things too small to see with the unaided eye - or small scale experimenting.

Matter and Change

Matter

• Anything that has _______________ and takes up _______________.

• Everything is made up of matter.

Definitions for Components of Matter

_______________ - the simplest type of substance with unique

physical and chemical properties. An element consists of only

one type of atom. It cannot be broken down into any simpler

substances by physical or chemical means.

_______________ - a structure that consists of

two or more atoms that are chemically

bound together and thus behaves as an

independent unit.

_______________ - a substance

composed of two or more elements

which are chemically combined.

_______________ - a group of two or more elements and/or compounds that are physically intermingled.

Definitions for Components of Matter

• _______________ - amount of matter the object contains - measured in grams.

• _______________ - matter that has uniform and definite _______________ (pure substances) - contain only one kind of matter.

Physical Properties• Quality or condition of a substance that

can be observed or measured without changing the substance’s composition.

• Color• odor• hardness• density• melting & boiling points• solubility

• Physical properties help chemists _______________ substances.

States of Matter

• _______________ - definite shape and volume.• Particles are packed tightly together.

• Almost incompressible.

• Expand only slightly when heated.

• _______________ - indefinite shape and definite volume.• In close contact with one another.

• Liquids can flow.

• Almost incompressible.

• Tend to expand when heated.

• _______________ - indefinite shape and volume.• Gas particles are far apart.

• Easily compressed.

• Expand without limit to fill any space.• _______________ - describes the

gaseous state of a substance that is generally a liquid or solid at room temperature (different than a gas).

Physical Change

• _______________ can be changed in many ways without changing the _______________ composition of the material.

• Cutting • Dissolving • Crack• Grinding • Melting • Boiling • Bending • Freezing • Crush• Tearing • Condensing • Break

Melting or Freezing of Water

• Melting ice into liquid is a physical change, along with changing liquid to steam and steam to condensation.

• There is no alteration to the chemical composition of water, only a change of state.

Classifying Mixtures

• _______________ blend of two or more substances.

• Compositions may vary.

Heterogeneous Mixture

• Not uniform in _______________.• If you were to separate the mixture into

portions, each portion would be different from the other.

Homogeneous Mixture

• Completely _______________ throughout.

• Components are evenly distributed throughout.

• Separate the mixture into portions and the portions would be the same.

• Also called _______________ - may be gases, liquids, or solids.

Atomic Structure&the Periodic Table

Early Models of the Atom

• John Dalton• English teacher• 1766-1844• Studied ratios of elements in

chemical reactions.• Formulated hypotheses and

theories to explain his observations and came up with Dalton’s atomic theory.

Dalton’s Atomic TheoryDalton’s Atomic Theory

1. All matter consists of ___________________.

2. Atoms of one element cannot be converted into atoms of another element.

3. Atoms of an element are identical in mass and other properties and are different from atoms of any other element.

4. _______________ result from the chemical combination of a specific ratio of atoms of different elements.

The Postulates

• His model was not accepted at first, however, he used his model to explain the existence of certain types of substances.

• He predicted correctly the formation of multiple compounds and his theory became widely accepted.

Atoms

• The smallest _______________ that cannot be divided any further and still maintain the _______________ of the substance.

Structure of an Atom

• J.J. (John Joseph) Thomson, physicist• 1890-1900• Showed that the atoms of any element can be

made to emit tiny negative particles - called _______________.

• Thompson knew that the entire atom was not negatively charged so he concluded that the atom must also contain _______________ particles that balance the negative charge, giving the atom a _______________ overall charge.

J.J. Thomson

• J.J. Thomson was chosen to head the Cavendish Laboratory in Cambridge, England in 1884 when he was only 28 years old.

• Thomson was known for his gift in designing experiments, but he was not mechanically inclined and needed help to build the apparatus needed to perform the experiments.

Structure of an Atom

• William Thomson (Lord Kelvin, no relation to J.J. Thomson)• ______________________________• He had the idea that the atom might be something

like a pudding with raisins randomly distributed throughout.

• He reasoned that the atom might be thought of as a uniform pudding of positives charge with enough negative electrons scattered within to counterbalance that positive charge.

Structure of an Atom

• Ernest Rutherford• 1911• Learned physics in J.J.

Thomson’s laboratory in the late 1890s.

• Main area of interest was the _______________particle (α particle) - positively charged particles with a mass approximately 7500 times that of an electron.

• Rutherford concluded that the plum pudding model for the atom could not be correct.

• The large deflections of the α particles could be caused only by a center of concentrated positive charge that would repel the _______________ charged α particles.

• Most of the α particles passed directly through the foil because the atom is mostly open space.

• Rutherford concluded that the plum pudding model for the atom could not be correct.

• The large deflections of the α particles could be caused only by a center of concentrated positive charge that would repel the positively charged α particles.

• Most of the α particles passed directly through the foil because the atom is mostly open space.

• By 1919, Rutherford concluded that the nucleus of an atom contained what he called _______________ (has the same magnitude of charge as the electron, but its charge is positive)

• Protons have a _______________charge and the electron a charge of _______________

• 1932, he and a coworker (James Chadwick) were able to show that most nuclei also contain a neutral particle that they name the _______________ (which has no charge)

• Mass and charge of the electron (e-), proton (p+), and neutron (N)

The mass and charge of the electron, proton, and neutron.

Particle Relative Mass* Relative ChargeElectron 1 1-Proton 1836 1+Neutron 1839 None*The electron is assigned a mass of 1 for comparison

Distinguishing Between Atoms

• Protons and electrons are equal in an atom of an element (_______________).

• The _______________of an element is the number of _______________ in the nucleus of an atom of that element. (If the p+ and e- are the same, then the atomic number will also identify the number of e-)

• The sum of the number of neutrons and the number of protons in a given nucleus is called the _______________.

• _______________• atoms with the same number of protons but

different numbers of _______________.• Elements on the periodic table are the most

common _______________ of those substances.

Distinguishing Between Atoms

• Isotopes• Because they have different numbers of

neutrons, their mass numbers will be different.

• Neon - 20• Neon - 21• Neon - 22• All of these are isotopes of neon.

Distinguishing Between Atoms

• Isotopes• 3 known isotopes of hydrogen

• hydrogen - 1 [hydrogen]• hydrogen - 2 [deuterium]• hydrogen - 3 [tritium]

Modern Day Atom• _______________ – negatively charged

subatomic particle that moves around the nuclear in different energy levels and sublevels

• _______________ – positively charged subatomic particle located in the nucleus of an atom

• _______________ – neutral subatomic particle located in the nucleus of an atom

Atom Lab

Elements and Compounds

Elements

• Simplest forms of _______________ that can exist under normal laboratory conditions.

• Cannot be separated into simpler substances by _______________means.

• Building blocks of other substances.

Compounds

• Two or more _______________ combined together.

• Can be separated into simpler substances only by chemical means.

Chemical Symbols

• Shorthand representation of an element.• The symbol may be the first or the first two

letters of the name of the element.• Some symbols are representative of the Latin

or Greek names for the element.• Represented by one, two, or, less often,

three letters.• First letter is always capitalized.• Second or third letter is always lower case.

Chemical Formulas

• Shorthand representation of a compound.• The subscript of a formula represents the

proportions of the various elements in the compound - the proportions are always the same for any one compound.

• H2O = water

• CO2 = carbon dioxide

• CO = carbon monoxide

Chemical Reactions

• One or more substances changing into new substances.

• Starting substances are the reactants.• Arrow dividing the two indicate “to

form” or “yields”.• Ending substances are the products.• ______________ ______________

Chemical Property

• The ability of a substance to undergo a _______________ reaction and to form new _______________.

• Chemical properties are only observed when a substance undergoes a chemical change.

• A chemical change always results in a change in the chemical _______________ of the substances involved.

• Burning• Decompose• Rust• Explode• Corrode• Rot

Conservation of Mass

• Law of Conservation of Mass• In any physical change or chemical

reaction, mass is neither created nor destroyed; it is conserved.

• The mass of the reactants equals the mass of the products.

Periodic Table of Elements

• Shows all the known elements and gives a lot of information about each element.

• Invaluable in chemistry!

Development of Periodic Table

• Elements in the same group generally have similar chemical properties.

• Properties are not identical, however.

Development of Periodic Table

Dmitri Mendeleev and Lothar Meyer independently came to the same conclusion about how elements should be grouped.

Development of the Periodic Table

Mendeleev, for instance, predicted the discovery of germanium as an element with an atomic weight between that of zinc and arsenic, but with chemical properties similar to those of silicon.

Dmitri Mendeleev

• First to officially organize the elements in an organized manner in 1869.

• Organized the elements according to their increasing atomic mass.

• Then he grouped them into columns and rows according to physical and chemical properties.• Row – _______________• Column - _______________

• Mendeleev had no idea what atoms were made of or why they behaved as they did.

• Nevertheless, he was able to put together the periodic table almost as we know it today--except that some elements were missing, because they were unknown in 1869.

Henry Moseley

• Rearranged the elements according to their _______________.

• Arranging the elements in this manner provided for a better fit of chemical and physical properties and aligned those elements that were discovered after Mendeleev developed the original periodic table.

Parts of the Periodic Table of Elements

• _______________ – substances to the left of the dark line

• _______________ – substances to the right of the dark line

• _______________ – those elements that border the line

Properties of Metal, Nonmetals,and Metalloids

Metals versus Nonmetals

Differences between metals and nonmetals tend to revolve around these properties.

Metals versus Nonmetals

• Metals tend to form _______________.• Nonmetals tend to form _______________.

Metals

Tend to be _______________, _______________, _______________, and good conductors of heat and electricity.

Metals

• Compounds formed between metals and nonmetals tend to be ionic.

• Metal oxides tend to be basic.

Nonmetals

• Dull, brittle substances that are poor conductors of heat and electricity.

• Tend to gain electrons in reactions with metals to acquire noble gas configuration.

Nonmetals

• Dull in appearance• May be a gas, liquid, or solid• Not ductile• Not mallable• Poor conductors of electricity and heat

Nonmetals

• Substances containing only nonmetals are _______________ compounds.

• Most nonmetal oxides are acidic.

Metalloids

• Have some characteristics of metals, some of nonmetals.

• For instance, silicon looks shiny, but is brittle and fairly poor conductor.

Fireworks• Potassium – combustible element that helps oxidize firework mixtures• Lithium – adds red color • Sodium – gold and yellow colors• Magnesium – bright white color• Calcium – deepens the colors of the other elements in the fireworks• Strontium – red color and stablizes other elements• Barium – green color and stablizes other elements• Titanium – produces the spark• Iron – produces sparks• Copper – blue color• Zinc – smoke clouds• Aluminum – silver and white sparks and flames – sparklers• Carbon – black powder• Phosphorus – fuel • Sulfur – fuel• Antimony – glitter effects

Groups of the Periodic Table

• Group 1 – _______________ metals• Group 2 – _______________metals• Group 11 – _______________ metals• Group 17 – _______________• Group 18 – _______________

Periodic Trends

Sizes of Atoms – Atomic Radius

The bonding atomic radius is defined as one-half of the distance between covalently bonded nuclei.

Atomic Radius

Ionic Size

• _______________ is a charged particle.• All atoms are neutral – the protons and

electrons are equal to one another.• The only way an atom becomes a

charged particle is if it _______________ or _______________ electrons.

Ionic Size

• _______________ – positively charged ions• Lost electrons – more protons than

electrons• Metals tend to lose electrons

• _______________ – negatively charged ions• Gained electrons – more electrons than

protons• Nonmetals tend to gain electrons

Ionic Size - Cations

• Cations are _______________ than their parent atoms.• The outermost

electron is removed and repulsions are reduced.

Ionic Size - Anions

• Anions are __________ than their parent atoms.• Electrons are

added and repulsions are increased.

• Ions increase in size as you go _____________ a column.• Due to

increasing value of the energy levels.

Ionization Energy

• Amount of energy required to _______________ an electron from the ground state of a gaseous atom or ion.• First ionization energy is that energy

required to remove first electron.• Second ionization energy is that energy

required to remove second electron, etc.

• It requires more energy to remove each successive electron.

• When all valence electrons have been removed, the ionization energy takes a quantum leap.

Trends in First Ionization Energies

• As one goes down a column,________energy is required to remove the first electron.• For atoms in the

same group, the valence electrons are farther from the nucleus.

Trends in First Ionization Energies

• Generally, as one goes across a row, it gets harder to remove an electron.