Chapter 10 NotesAtomic

Structure & The Periodic

Table

Atomic Structure

Element - only one kind of atom - Cannot be further broken down

ex- Pb, Cu, Ne, He, H, O, C

Periodic Table-Table of 114 elements know to man

-90 naturally occurring Earth -24 artificially made in labs

The ATOM

Smallest part of an element

Still has properties of that element

Greeks atomos = indivisible

4 models:

Dalton 1803

-solid sphere/indestructible-element made of same atoms

Thompson 1897

-chocolate chip cookie/plum pudding-sphere + charge-in sphere - charges=electron

Rutherford/Bohr 1913

-solar system model-dense center = nucleus-nucleus +charge- -charged particles orbit nucleus

Present Model 1926

-nucleus + charged particles = proton-nucleus 0 charged particles = neutrons-cloud – charged particles = electrons constantly moving

Electron Cloud

Drawing Atomic ModelsElectron Cloud-area where electrons move speed of light

- electron levelsex/2, 8, 18, 32 ….

Level 1: 2e-

Level 2: 8e-

Level 3: 18e-

NucleusProtons p+Neutrons, n

atomic # = p+ = e-

mass # - atomic # = n0

atomic mass = avg of all isotopes

4Be

Beryllium9.01218

Atomic numberSymbolElement nameAtomic mass

Isotopes

Atoms of the same element with different numbers of neutrons

ex.Carbon normal C-12 (6 p+ & 6 n0) isotope C-14 (6 p+ & 8 n0)

Periodic Table• 1834 – 1907 Russian chemist

Mendeleev arranged all elements known 1900 by mass

• Found patterns• Predicted mass & properties of

undiscovered elements• Problems? atomic #s didn’t match up

when arranged by properties• New table – atomic #s match up

Valence electrons• Electrons in the out most energy level

of the atom• Corresponds with the Period number

on the periodic table • Lewis dot diagrams illustrate the

valence electronsCarbon has 4 valence electrons

Table Parts• Period – horizontal row of the table• Family/Group – vertical columns

elements have similar properties

Group 1 – Alkali Metals

• Conduct heat & electricity• Soft, low m.p. & low density• React with acids• Very reactive, never found as free

elements• Malleable, ductile, luster• 1e- in outer energy level (+1 cation)• Identified by flame test

Group 2 – Alkaline Earth Metals

• Highly reactive, never found free in nature

• Low density• React with acids• 2e- in outer energy level (+2 cation)• Identified by flame test

Group 3 – 12: Transition Metals

• Common metal, properties vary• High m.p. - react with acids• Brittle, soft, strong, hard, malleable, ductile• Alloys – mixture of 2 or more metals to gain

desired characteristics• +2 - +4 cations• Ores – mineral or other natural material from

which one or more metals can be obtained

Groups 13 – 17: Nonmetals• Insulators for electricity, dull, brittle• Not reactive w/ acids• Solids, liquids & gases• React with metals to form compounds

– Group 17: Halogens• Form salts, all 3 states @ room temp• Toxic, different colors

– Metalloids• Properties of metal & nonmetals• stairstep

Group 18 : Noble Gases

• Perfect elements • 8 valence electrons• Inert- not reactive

Diatomic Seven• 7 elements that exist as 2 atoms

combined together in nature–Hydrogen–Nitrogen–Oxygen–Fluorine–Chlorine–Bromine–Iodine

Chapter 12 Notes

Elements & Properties

Metallic Bonding

• Not ionic or covalent• Positively charged ions surrounded

by “sea of electrons” • Outer electrons move freely

Flame Tests• Certain elements can be identified

by the color of flame they produce

Transiton Elements• Bright colors of gemstones• Iron, cobalt & nickel = magnetic fields• Copper, gold & silver = coins• Mercurcy – liquid @ room temp.• Ores – metals in the Earths Crust

Synthetic Elements

• Made by combining existing elements w/ fast moving particles

• More than 92 protons = transuranium• Unstable breakdown quickly

Radioactive Elements• Nucleus breaks down giving off

particles & energy• Becomes other elements as the

number of protons change

Nonmetals• Diatomic 7• Less reactive further down the column• Halogens & Noble gases• Sublimation – solids change into vapors

- ex. Iodine

Hydrogen• Smallest element• Uniquie properties – in a group of its

own

Mixed Groups• Semiconductors – conduct electric

current under certain conditions• Allotropes – different forms of the

same element– Graphite & diamonds = carbon– O2 & O3 both are oxygen

Ozone = O3

Oxygen molecule O2