The Periodic Table and Atomic Structure

Section 2.1

Four classical atomic models Quantum Mechanical Model

Review

Distinguish between metals, non-metals, and metalloids in terms of distinguishing properties

Explain the structure of the periodic table Identify important families and elements Describe atomic theory in terms of subatomic particles and

location (nucleus, energy levels) Define atomic number, mass number, isotope, and atomic

molar mass and be able to identify these for a given element Determine numbers of protons, neutrons and electrons for a

given element Describe the process of ionization and formation of cations and

anions Identify patterns in the periodic table for valence electrons and

energy levels Relate ionization to the octet rule

Objectives

Antoine Lavoisier Mass is neither created or destroyed The total mass of the reactants equals the

total mass of the products

Law of Conservation of Mass

115: basic building blocks 90 naturally occurring, 25 synthetic Split into 3 classes

◦ Metals◦ Non-metals◦ Metalloids

◦ https://www.youtube.com/watch?v=GFIvXVMbII0

The Elements

Most elements (75%) Silver/grey and shiny Conductors of heat and electricity Malleable and ductile Most solid at room temperature Reactivity varies

◦ Most reactive is francium (left and down)◦ Inert= unreactive

Metals

17 elements Grouped based on their different from

metals Vary is state, color and reactivity

◦ Highly reactive= fluorine (right and up ◦ Inert= noble gases

About half will appear at molecules (more than one atom)

Non-Metals

Remaining elements Properties intermediate between metals and

non-metals Along the staircase (except aluminium) Ex. Silicon, arsenic, boron

Metalloids

The Periodic Table

Organizes elements based on chemical properties◦ Metals on left side and centre◦ Non-metals on far right

Exception hydrogen (learn more later)◦ Metalloids between two

Shows name and symbol for element◦ Get to know the symbols!

http://periodictable.com/

The Periodic Table

For the following, identify as being a metal, non-metal or metalloid

Hydrogen Sulfur Calcium Tin Gold Boron Aluminum Xenon

The Element Game

For the following, give the element’s name or symbol:◦ Calcium◦ Hydrogen◦ Sulfur◦ Phosphorus◦ Mg◦ Na

Pre-test

Vertical columns Groups of elements with similar

chemical/physical properties Group 1: alkali metals

◦ Soft, shiny, silver, very reactive with water◦ Compounds white and soluble in water

Group 2: alkali earth metals◦ Shiny, silver◦ White compounds but not as soluble

Important Families/ Groups

Group 17: halogens◦ Non-metals◦ Very reactive

React with alkali metals to make salts Group 18: noble gases

◦ Non-metals◦ Very unreactive

Important Families cont…

Horizontal rows Have the same number of levels of

electrons

Periods

Crossword What’s in a Name? ELEMENTary My Dear Watson

To Do

Atoms are very small (10-10 m in diameter) What are three kinds of subatomic particles?

◦ Protons, Neutrons and Electrons Where are they found?

◦ Protons and Neutrons- inside the nucleus◦ Electrons- outside the nucleus

Protons and neutrons are over 99.9% of total mass◦ Imagine this: our classroom filled with iron. If we take

out the nuclei for all the iron atoms and place them side by side, they would be as big as a period in a book. But that period would almost equal the mass of the room full of iron

Atomic Theory

Has a positive charge (p+) Mass of 1.67x10-27 kg The number of protons defines the element

and is called the atomic number

All helium atoms have a 2 p+ and every atom with 2 p+ is helium

Protons

No charge (n0) Mass of 1.67x10-27 kg The number of protons and neutrons

together make the atomic mass of the atom◦ If an atom has 8 protons and 10 neutrons, its

atomic mass is 18◦ If an element has an atomic number of 24

(protons) and an atomic mass of 52 (protons and neutrons) it has 28 neutrons

Neutrons

Charge of 1- (e-1) Mass of 9.11x10-31kg Electrons are so small that they are not

factored into the atomic mass In an atom the number of protons = the

number of electrons

Electrons

Number of protons Determines the element

Atomic Number

Can you find the atomic number of the following elements?PbHgtinchlorineplatinumCumanganeselithium

As we move through the periodic table, what do you notice about the ordering of atomic numbers?

Isotope- atoms of same element with different number of neutrons◦ Ex. Common form of hydrogen has one proton

and no neutrons. 1/10 000 hydrogen atoms have a neutron, called deuterium (“heavy” hydrogen)

Each isotope given a mass number◦ Equals total number of protons and neutrons

(don’t include electrons- too small)◦ # of neutrons= mass number – atomic

number

Mass Number and Isotopes

Can be shown as:

◦ Mass number

element symbol atomic number

Ex. Oxygen-16

What would be the symbols for oxygen-17? Oxygen-18?

Mass Number and Isotopes cont…

Mass number and isotopes

Name:#p = _____#n = _____#e = _____

Name:#p = _____#n = _____#e = _____

Practice: Fill in the chart!Element Name

Mass Number

Number of Protons

Number of Neutrons

calcium 41

uranium 238

aluminum 14

9 5

20 10

iron 30

Shown in the periodic table Average mass of element’s isotopes Number of electrons equals number of

protons (in neutral atoms)

Atomic Molar Mass

Atomic molar mass

Neils Bohr- proposed that electrons moved around a nucleus at a specific fixed distance◦ Energy level

Electrons could move up levels by absorbing energy

Electrons could move down levels by losing energy

BUT each energy level can only have a certain maximum number of electrons

Bohr Model of the Atom

Electrons occupy energy levels◦ Region around nucleus either empty or contain

electrons◦ Increase energy when get further from the

nucleus Specific number of electrons/level

◦ First level- 2 electrons◦ Next levels- 8 electrons

Energy level can be empty, partly or completely filled

Energy Levels

Drawings include:◦ Number of protons (in nucleus)◦ Number of neutrons (in nucleus)◦ Electrons in correct energy levels (how many electrons can be in each

level?) Ex. Hydrogen Lithium Sodium Oxygen Sulfur Helium Neon Argon Calcium

Drawing Atoms

Electrons in the outermost energy level Valence number- number of electrons an

element can lose/gain to combine with other elements

How many valence electrons do each of the following elements have?◦ Oxygen?◦ Magnesium?◦ Chlorine?◦ Argon?◦ Carbon-14?

Valence Electrons

For understanding how atoms bond Atoms want to have eight electrons in their

valence shell (which shell is this?) More stable when have full energy levels What are these elements like with full energy

levels?◦ Noble gases!◦ Gain/lose electrons to be like their closest noble gas◦ Ex. Chlorine will gain one electron to be like argon◦ Exception: hydrogen, lithium and beryllium. Why?

Who do they want to be like?

The Octet Rule

When we gain/lose electrons from an atom, what happens to its charge?◦ Ex. Fluorine gains one electron to fill its outer

octet. What is its electrical charge now? Gaining/losing electrons process called

ionization◦ Results in positively charged or negatively

charged ions

What Now?

Elements can lose or gain outermost (valence) electrons◦ Called ionization◦ Makes ions (positively or negatively charged)◦ Allows metals and non-metals to form

compounds◦ http://www.youtube.com/watch?

v=xTx_DWboEVs&feature=related

Formation of Ions

Positively charged ions Metal ion loses electrons Where do the electrons go?

◦ To another atom Why would the atom be positively charged if

it loses electrons? Ex Magnesium

◦ Loses 2 electrons◦ What would the diagram look like before? After

ionization? Put charge as a superscript: ex. Mg2+

Cations

Negatively charged ions Non-metal gains electrons Where do the electrons come from?

◦ From atoms that lose electrons (cations) Why is it negatively charged? Ex. Oxygen

◦ Gains two electrons◦ What is the diagram before? After ionization?

How would you write it as a symbol?

Anions

Cations:◦ Element name + ion◦ Ex. sodium ion◦ Ex. magnesium ion

Anions:◦ First part of element name and change ending to

“ide”◦ Ex. nitride ◦ Ex. oxide◦ Ex. fluoride

Naming Ions

For each of the following ions, draw with nucleus and electrons and give appropriate name or symbol:

Hydrogen ion Cl- Nitride Be2+

sulfide

Practice

group 1 = 1+ group 2 = 2+ group 3-12 labeled on table group 15 = 3- group 16 = 2- group 17 = 1- group 18 not ions B, C, Si do not form ions

Ion Trends in Periodic Table

Why do atoms gain or lose electrons?◦ To have full energy levels and be more stable like

closest noble gas Once ions are formed:

◦ Electrically charged◦ What would happen when I bring a cation and an

anion together?◦ Form a bond! How we make compounds between

metals and non-metals◦ Need to form the ion first before a bond can

be formed

Why form ions?

Building an Atom Assignment

TO DO