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... H 2 F 2 O 2 Cl 2 N 2 Br 2 I 2

Formulas Molecular Formulas - shows the kinds and numbers of atoms present in a molecule of a compound. We cannot determine the shape or geometry. CO 2 – 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 three- dimensional 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