Electrons and the Periodic TableMrs. Freeman

History• HOW WAS MENDELEEV’S PERIODIC TABLE

ARRANGED? ▫By their chemical properties

•  HOW IS THE MODERN PERIODIC TABLE ARRANGED?▫By increasing number of protons and atomic

mass.• WHY DIDN’T MENDELEEV ARRANGE HIS

TABLE THIS WAY?▫Because at the time the number of protons was

not known.

PERIODS: are a horizontal row of elements.•HOW MANY: 7•VARIATION ACROSS A PERIOD:

Changes from metals to metalloids to nonmetals

GROUPS AKA FAMILIES: the individual columns of elements.•HOW MANY?

▫18•SIMILARITIES BETWEEN ELEMENTS

IN THE SAME GROUP?▫They have the same number of valence

electrons

THREE CLASSES OR CATEGORIES OF ELEMENTS ON THE PERIODIC TABLE

METALS NONMETALS METALLOIDS

LOCATION Left side of the stair step line

Right side of the stair step line

Along the stair step line

EXAMPLES AND USES

Zinc-vitamins and certain containers.

Potassium-in bananas for cells to use

Oxygen-gas to breathe

Carbon-foundation for life.

Aluminum- cans, canisters, cars.

Silicon-sealant against water

PROPERTIES Hard, malleable, durable, rust, dense

Not dense, colorless,

Has properties of both metals and non-metals.

REACTIVITY PATTERN WITHIN A GROUP: increasing reactivity, decreasing melting and boiling point and density generally increases,

•Left side of the table

Metals

•Right side of the table

Nonmetals

ALKALI METALS

ALKALINE EARTH METALS

BORON FAMILY

CARBON FAMILY

NITROGEN FAMILY

OXYGEN FAMILY

HALOGENS

NOBLE GASES

GROUP # 1 2 13 14 15 16 17 18LIST OF ELEMENTS IN GROUP

HydrogenLithiumSodiumPotassiumRubidiumCesiumFrancium

BerylliumMagnesiumCalciumStrontiumBariumRadium

BoronAluminumGalliumIndiumThallium

CarbonSiliconGermaniumTinLead

NitrogenPhosphorusArsenicAntimonyBismuth

OxygenSulfurSeleniumTelluriumPolonium

FluorineChlorineBromineIodineAstatine

HeliumNeonArgonKryptonXenonRadon

# of valence electrons

1 2 3 4 5 6 7 8

Key Facts

Prop. AndReactivity

Uses

Are very reactive.

Form Ionic CompoundsMetal

Ex. Salt

React with halogens well.

Form ionic compounds.Metal

Ex. Magnesium chloride

Forms covalent compounds

Non-metals

Boron is metalloid.

Forms both covalent and ionic bonds.

2 metals and 2 metalloids

Forms covalent bonds.

Non-metals

Basis for fertilizer

Forms covalent and ionic bonds.

Most abundant elements in earths crust.

All are non-metals.

Form ionic compounds.

Most reactive group.

Inert-do not react

•THE MOST REACTIVE METALS: ▫Francium, Cesium, and Rubidium (in order

from most reactive to least reactive)•THE MOST REACTIVE NONMETALS:

▫Fluorine, Chlorine, and Bromine (in order from most reactive to least reactive)

Excited electron-

•an electron in an energy level higher than its ground state (it has absorbed energy)

Ground state-

•all the electrons have the lowest possible energy.

Energy Level-

•The possible energies that electrons in an atom can have.

Sub-level

•Electron orbital designated s, p, d or f. •These sublevels or orbitals have

characteristic shapes which can be used to explain and predict the chemical bonds that atoms can form.

Orbital-

•the region of space around the nucleus where an electron is likely to be found.

Energy level/energy shell-

•the possible energies that electrons in an atom can have.

Three ways to show arrangements of electrons

•Orbital Configuration Notation•Electron Configuration Notation•Electron Dot Notation

Electron configuration-

•specific distribution of electrons in atomic orbitals of atoms or ions.

Valence shell-

•the outside energy shell

Valence electrons-

•an electron that is in the highest energy level of an atom.

Orbital Configuration Notation•each electron is assigned a space with an

up spin or a down spin.•All up spins must be placed first.•Then place all down spins until all

electrons are used.

Electron configuration notation:•is just the letters and numbers from the

orbital configuration.•Example: Ar= 1s2 2s2 2p6 3s2 3p6

Electron dot notation:

•the valence electrons represented by dots around the element symbol.

• -fill in using the house memory trick

Hund’s Rule

•every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.

Aufbau Principle:

•is used to determine the electron configuration of an atom, molecule or ion. The principle postulates a hypothetical process in which an atom is "built up" by progressively adding electrons.

Pauli’s Exclusion Principal

•“no two electrons in the same atom can be in the same quantum state.” [1] This means that no two electrons can have the same set of quantum states of: 1) energy, 2) angular momentum magnitude, 3) angular momentum orientation, and 4) orientation of intrinsic spin.

Assessment

• LIST THE PERIOD TO WHICH EACH OF THE FOLLOWING BELONGS:▫STRONTIUM:

5 ▫ IRON:

4 ▫RADON:

6 ▫ANTIMONY:

5• HOW MANY ELEMENTS ARE IN PERIOD 4?

▫18 • HOW MANY ELEMENTS ARE IN PERIOD 6?

▫32

Assessment:

•NAME THE ELEMENT IN GROUP 3 PERIOD 4 ▫Scandium.

•HOW MANY VALENCE ELECTRONS ARE IN AN ATOM OF FLUORINE? ▫7

•TO WHAT GROUP DOES CARBON BELONG ▫14