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?