Matter: all matter is made up of atoms. is anything that has a mass and a volume all matter has a specific density or arrangement of atoms that can be used to identify it.

John Dalton (aka Jack) 1. Atoms are the smallest form of matter 2. Atoms make up all matter 3. Atoms of the same element are the same 4. Atoms cannot be broken down 5. Atoms combine in specific ratios

Thomson: Discovered the electron First model of atom

Rutherford: Discovered presence of nucleus And protons Atom was mostly empty space

Chadwick: Discovers the neutron

Bohr: Suggested electrons move in energy Levels Presents model used today (although not completely accurate)

M shell L shell + n K shell nucleus

Electron cloud model Electron cloud Nucleus Neutron Proton

PERIODIC TABLE Elements: roughly 88 naturally occurring roughly 20 man made organized arrangement metals, nonmetals, metalloids, noble gasses pure substance

Protons Positively charged Found in the nucleus Identifies element Gives the element its atomic number Gives nucleus its positive charge Contributes to the atom’s reactivity +

Protons Positively charged Found in the nucleus Identifies element Gives the element its atomic number Gives nucleus its positive charge Contributes to the atom’s reactivity +

ELECTRONS Negatively charged Found on the energy shells Determines the reactivity of the atom Has very small mass-not normally considered when calculating mass of atom. e

ATOMIC MASS: no. protons + neutron -- ATOMIC NUMBER: no. protons _________________________________ no. neutrons

Li At. Mass 7 -- At. # 3 4 Protons: 3 Neutrons: 4 ___________________________ 4 Protons: 3 Neutrons: 4 Electrons: 3* *all unbonded atoms are electrically and chemically neutral. # of + = # of e.

Isotopes: Atoms of the same element that Differ from each other by the number of Neutrons. Isotopes have the same Atomic number but A different Atomic Mass. 45 known isotopes of iodine I 127, 53 I 136, 53 15 known isotopes of carbon C 12, 6 C 14, 6

Element – pure Compound – 2 or more elements chemically combined homogeneous Mixture – 2 or more elements, compounds, or both physically combined. homogenous or heterogeneous

Element – pure Compound – 2 or more elements chemically combined homogeneous Mixture – 2 or more elements, compounds, or both physically combined. homogenous or heterogeneous

Liquids: indefinite shape definite volume MA faster than solid *MD larger than solid

Gas: Indefinite shape Indefinite volume MA fast Ma weak MD large

MA, MD increased by increases in Temperature = increases in energy. Increases in MA and MD = changes in state.

State changes are a result of increases State changes are a result of increases* in thermal energy which directly increases* MD and MA. MA MD Decrease KE dec condensation vaporization MA MD Increase KE inc melting freezing

Bohr model Atomic mass = 7 Atomic number = 3 = 3 n = 4 e = 3 Lithium 3 = 3 n = 4 e = 3 3 + + n 4 Electron configuration: 2-1

Li F The outer most shell is called the valence shell and is often unstable, meaning It does not contain the octet number of electrons In order for the atom to become stable or Fill the shell to the octet rule, this shell will be The one to bond. Li F

Atoms that are not stable cause trouble – they can be flammable, explosive, toxic. These problems are what make an atom reactive – meaning they want to become stable. Bonding: Ionic loss or gain of electrons Covalent sharing of electrons

IONIC BONDING: OCCURS BETWEEN- METALS: LESS THAN 4 VALENCE ELECTRONS AND NONMETALS: MORE THAN 4 VALENCE ELECTRONS ***REMEMBER: ATOMS WANT TO USE LITTLE E!! METALS WILL LOSE ELECTRONS NONMETALS WILL GAIN THOSE ELECTRONS LOST

Ionic Bonding: occurs between metal and nonmetal > 4 val. e < 4 val. E lose e gain e form ions – charged atoms because the # of protons does NOT equal # electrons. + ion - ion

- Na: metal, > 4 val. e, lose e F: nonmetal, < 4 val. e, gain e + - F: nonmetal, < 4 val. e, gain e NaF sodium flouride

+ - Li2O

Bonding between atoms is a result of: a. atoms need to be stable b. atoms need to exist in a lower energy state c. attraction of positive nucleus and negative electrons d. size of the atom’s radius

COVALENT BONDING SHARING OF ELECTRONS ATOMS REMAIN NEUTRAL OCCURS BETWEEN: 2 NONMETALS A NONMETAL AND A METALLOID HYDROGEN AND ALL NONMETALS PRODUCES WEAK BONDS PRODUCES COMPOUNDS THAT HAVE LOW MELTING POINTS ALL ORGANIC COMPOUNDS ARE COVALENT

COVALENT BONDS Between hydrogen and A nonmetal Hydrogen has only one Electron and therefore will never Lose that electron. In order for It to become stable and exist In a lower energy state, it will Share its only electron with fluorine Fluorine has 7 valence electrons It needs 8 in order to exist in a lower Energy state. It could bond ionically With A metal or covalently with hydrogen by sharing one of its valence electrons.

COVALENT BONDINGBETWEEN 2 NONMETALS Nonmetals, because they have more than 4 valence electrons and especially those that have small atomic radii, will bond with them- selves in order to become stable and exist at a lower energy state. These atoms will be called DIATOMS. There are 7 diatoms That you will need to memorize. They are F, Cl, Br, I, O, N, H.

NONMETAL AND A METALLOID COVALENT BONDING BETWEEN NONMETAL AND A METALLOID Carbon will be our only metalloid with 4 valence electrons Fluorine is a Nonmetal with 7 Valence electrons The resulting stable cmpd Contains 4 F and 1 C. Because the atoms never LOST E’s they remain neutral.

A NONMETAL AND A METALLOID HYDROGEN AND ALL NONMETALS Comparison of bonds Ionic Bonding: occurs between metal and nonmetal lose e gain e form ions – charged atoms COVALENT BONDING SHARING OF ELECTRONS ATOMS REMAIN NEUTRAL OCCURS BETWEEN: 2 NONMETALS A NONMETAL AND A METALLOID HYDROGEN AND ALL NONMETALS

+ POLARITY __ On polar molecules, electrons are controlled by one UNEVEN DISTRIBUTION OF CHARGES + __ On polar molecules, electrons are controlled by one Of the atoms.

Chemical and physical comparison Physical properties Chemical properties Properties that describe the physical appearance of matter, such as size, shape, texture, density. Properties can change and be returned to original properties. Properties may be size dependent or size independent. Properties describe the chemical composition of the matter, such as the elements that are bonded and the specific ratio; H2O, Fe2O3. Chemical properties do not change without changing the composition of matter. Properties are not affected by size.

Chemical and Physical changes Chemical Changes The changes affect the way the matter appears; size, color, shape. These changes can be reversed. The properties of the new matter are the same as the original. The changes affect the appearance of matter. The changes change the chemical composition of the matter. These changes cannot be reversed. The properties of the new matter are different than the original.