PRE-CHEM CH. 3 Atoms and the periodic table
Dec 26, 2015
PRE-CHEM CH. 3Atoms and the periodic table
PRE-CHEM CH. 3 LO Describe the emergence of the Periodic Table
Determine an elements: protons, neutrons, electrons, family, period, atomic mass, atomic number.
Describe patterns on the Periodic Table, including relationship between electrons and group characteristics
Determine a Determine an elements electron energy level
Convert between moles and mass
ATOMS Every element is made of tiny, unique particles called atoms that cannot
be subdivided
Atoms of the same element are exactly alike
Atoms of different elements can join to form molecules
VARIATIONS ON THE ATOM Aristotle
Democritus
Dalton
Bohr
ELECTRONS Energy levels- e- can only be in certain E levels, they must gain E to move
to a higher level or lose E to move to a lower E level
Valence electrons
WHAT AN ATOM CONSISTS OF
PERIODIC TABLE KEY
DETERMINING THE MAKE UP OF AN ELEMENT
Element Protons (p+)
Electrons (e-)
Neutrons (n)
Atomic mass
Atomic number
C 6 6 6 (12.01)12
6
Mg
O
Zn
Fe
ATOM VS. IONAtom
P+ and e – are equal
Atomic number = #p+
No charge
Neutrons plus protons= atomic mass
Ion
P+ and e – are NOT equal
Atomic number = #p+
Charge Cation Anion
Neutrons plus protons= atomic mass
HOW TO FIGURE OUT ELECTRONS IN AN ION Charge= protons- electrons
-2= 10 protons – X electrons X = 12 electrons
+3 = 10 protons – X electrons X= 7 electrons
ATOM OR ION PRACTICEElement Atom/ion A Mass A# p+ e- n
O2- Ion 16 8 8 10 8
Mg+2
Na+
Na
Fe+3
ISOTOPE Hydrogen
Protium Deutrium Tritium
Isotopes Carbon 12, 13, 14 Hydrogen 1, 2, 3, Nitrogen 12, 14
PERIOIDC TABLE LAY OUT
QR code periodic table
QR CODE TO PERIODIC TABLE.. NO WAY!
Open and scan each element to hear a short video on it, courtesy of University of Nottingham
FAMILIES OF ELEMENTS
ALKALI METALS (GROUP 1)
All alkali metals have 1 valence electron
Alkali metals are NEVER found pure in nature; they are too reactive
Reactivity of these elements increases down the group
Group info from sciencegeek.net
Potassium, K reacts with
water and must be stored in
kerosene
ALKALINE EARTH METALS (GROUP 2)
All alkaline earth metals have 2 valence electrons
Alkaline earth metals are less reactive than alkali metals
Alkaline earth metals are not found pure in nature; they are too reactive
The word “alkaline” means “basic” common bases include salts of the metalsCa(OH)2
Mg(OH)2
PROPERTIES OF METALS
Metals are good conductors of heat and electricity
Metals are malleable Metals are ductile Metals have luster
TRANSITION METALS
Copper, Cu, is a relatively soft metal, and a very good electrical conductor.
Mercury, Hg, is the only metal that exists as a liquid at room temperature
PROPERTIES OF METALLOIDS They have properties of
both metals and nonmetals.
Metalloids are more brittle than metals, less brittle than most nonmetallic solids
Metalloids are semiconductors of electricity
Some metalloids possess metallic luster
SILICON, SI – A METALLOID Silicon has metallic luster Silicon is brittle like a
nonmetal Silicon is a semiconductor
of electricity
Other metalloids include:
Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te
NONMETALS Nonmetals are poor
conductors of heat and electricity
Nonmetals tend to be brittle
Many nonmetals are gases at room temperature
Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.
EXAMPLES OF NONMETALS
Sulfur, S, was once known as “brimstone”
Microspheres of phosphorus, P, a reactive nonmetal
Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure
HALOGENS Halogens all have 7 valence
electrons Halogens are never found pure
in nature; they are too reactive Halogens in their pure form are
diatomic molecules (F2, Cl2, Br2, and I2)
Chlorine is a yellow-green poisonous gas
NOBLE GASES
Noble gases have 8 valence electrons (except helium, which has only 2)
Noble gases are ONLY found pure in nature – they are chemically unreactive
Colorless, odorless and unreactive; they were among the last of the natural elements to be discovered
ELECTRON ENERGY LEVELS
orbital
P ORBITAL
D ORBITAL
F ORBITAL
ELECTRON CONFIG EXAMPLES H
B
O
Mg
N
Fe
Zn
NOBLE GAS CONFIG (SHORTHAND) Use the noble gas before your element, put it in [brackets]
Mg example: [Ne]
Subtract that many e- from your total 12-10= 2
Keep going up until you have used all your e-
3s2
Answer Mg= [Ne] 3s2
NOBLE GAS CONFIG EXAMPLES B
O
Mg
N
Fe
Zn
USING MOLES Avagadro’s number
6.022 x 1023 is a mole of a substance (gumballs, H, He, etc)
Molar mass= 1 mole
CONVERSION EX. WITH MOLAR MASS Fe= 5.50 mol Fe
mm= 55.85 g/mol Fe
Mass of Fe?
5.50 mol Fe 55.85 g Fe 307 g Fe
1 mol Fe
MORE…. 2.50 mol S is how many g S?
0.50 mol C is how many g C?
352 g Fe is how many mol Fe?
620 g Hg is how many mol Hg?
11g Si is how many mol Si?