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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