IGCSE Coordinated Sciences Y1

Unit 2: ChemistryC01, C03, C8.4, C4

Key Notes

Physical and Chemical Changes

• Read pages 47 in your textbook.• What is a chemical change?• How is it different from a physical

change?• Describe some indicators that tell us

a chemical change has occurred.

Physical or Chemical?Demo Physical? Chemical?

Both?Explanation

Heating Wax

Burning a Candle

Sugar and Water

CuCl2 and Al foil

Tearing Paper

Colored Water

KI and Pb(NO3)2

Vinegar & Baking Soda

Evidence of Change…

Evidence of Physical Changes• Change in phase or state

• Example: liquid → solid

• Mass or volume change• Color change that is not permanent

Evidence of Change…

Evidence of Chemical Changes• Energy is given off or taken in• Light is observed • Heat is given off• Bubbling or fizzing• Permanent color change

What is everything made of?

• Important vocabulary:– atom, – element, – molecule, – compound, – mixtures

• Write a definition & draw a picture for each term using pg. 30, 31, 46, & 54

• Then, write about the similarities and differences between each.

Sentence starters

• An element is unique because it…• Molecules are similar to compounds

because…• A molecule is different than a

compound because …• A mixture is different than either a

compound or molecule because…

What is inside an atom?

• Read & take notes on the description of an atom on Page 32 - 33.

• Watch the video clip about structure of an atom.

Atom Summary

• Fill in the table with information about the different parts of an atom:

Particle Charge Location in atom

Relative Mass

Proton

Neutron

Electron

Silent Teacher

• We are going to play a game to determine what you remember about atoms.

• As you start to recognize patterns, fill in your chart. Have your teacher check your work, then if asked, write up an answer on the group chart.

• Discover the patterns and then write the rules if you figure them out!

Quick Tour of the Periodic Table

• Atomic number• Atomic mass / nucleon number• Periods vs. Families• Metals, transition metals, non-

metals, noble gasses

Practice/ Review

Element p+ e- n0

HydrogenSulfurIodineSodium

Isotopes

• How can an element like Chlorine have an atomic mass of 35.5?

• Isotopes are atoms of the same element (same proton number) with different numbers of neutrons.

• Most elements have isotopes!

Chlorine

• Chlorine – 35 has an atomic mass of 35. How many protons does it have? How many neutrons?

• Chlorine – 37 has an atomic mass of __.p+ = _____ no= ______

• Of all the chlorine atoms in the world, 75% are chlorine-35 and 25% are chlorine-37, giving an average atomic mass of 35.5.

Atomic Orbitals

• Electrons travel around the nucleus in orbitals. • We will study the first 3 orbitals:

– The first orbital can hold up to 2 electrons– The second orbital can hold up to 8 electrons– The third orbital can hold up to 8 electrons

• Orbitals always fill from the inside out.• Example: Lithium 

Example Atom

• Example: Lithium 

Try These

Try these:• Hydrogen

 • Aluminum

Practice Time!• Obtain a “building atoms” sheet on

Haiku. • Use your baggie of particles to build

each atom from the sheet, recording your results in your journal.– Be sure to put the correct number of

electrons in each orbital and show the number of protons and neutrons in the nucleus!

– Put your name on your baggie and save your particles for later. You’ll get to eat them later

Electronic Configurations

• Scientists use a shorthand to denote how many electrons are in each orbital or energy level of an atom.

• See Page 36 for an example!• Go back to your atom drawings and

write the electronic configurations for each atom you built.

A FULL outer shell

(valence electrons)

What does every atom want?

Gaining and Losing Electrons

ION: an atom that has gained or lost electrons.

• Cation: An atom that has lost one or more electrons. Positively charged.

• Anion: An atom that has gained one or more electron. Negatively charged.

Becoming an ion…

How many electrons must be gained or lost by each atom? • Lithium • Argon • Chlorine • Potassium • Phosphorus • Magnesium 

Trends on the Periodic Table

• Group 1 loses one electron; they all have +1 charge.

• Group 6 gains two electrons; they all have a –2 charge.– Group I +1– Group II +2– Group III +3– Group V -3– Group VI -2– Group VII -1– Group VIII 0

Forming an Ionic Compound

• How do metals and nonmetals come together to form IONIC bonds?– Explain in your notes using an example

from your reading on page 50 – 51.– Show using your baggie of candy

“particles” the formation of:• Lithium + Fluorine

(how many of each atom do you need?)• Lithium + Oxygen

(how many of each atom do you need?)

Arrangement of Particles in Ionic Compounds

• When sodium and chlorine bond, they form a lattice structure made up of repeating units of positive and negative charges.

• Building a lattice structure

Lattice Structure

Forming Compounds

• Determine the formula for the compound made when the following atoms combine…–Magnesium + Bromine

– Sodium + Oxygen

– Aluminum + Fluorine

Simple Ionic Compounds

• How to write and name ionic compounds! – When writing the formula, first write the

symbol and charge of each ion.• Switch the charges and write them as subscripts.• Simplify!

– When naming a compound, write the name of the cation first then the anion with an –ide ending.

– Use roman numerals for ions with more than one charge [i.e. Fe+3 would be Iron (III), Fe+2 is Iron (II)]

Practice  Chloride, Cl-

1

Bromide, Br-1

Oxide, O-2

 

Sodium, Na+1

 

Magnesium, Mg+2

 Aluminum, Al+3

 

  Chloride, Cl-1

Bromide, Br-1

Oxide, O-2

 Sodium, Na+1

 

NaCl NaBr Na2O

Magnesium, Mg+2

 

MgCl2 MgBr2 MgO

Aluminum, Al+3

 

AlCl3 AlBr3 Al2O3

Ionic Compounds with Polyatomic Ions

• A Polyatomic Ion is an ion made up of more than one type of atom.

• Most have a negative charge, with the exception of ammonium.

• Ionic Compounds with polyatomic ions are written and named in the same manner as binary compounds.

Ionic Compounds with Polyatomics

The only exceptions are:• Each polyatomic ion is treated as one element

• Parenthesis are used around the entire ion when expressing the quantity necessary to balance out the charge– Ex. Cu+2 + OH-1 Cu(OH)2 and is named Copper (II)

Hydroxide

• Polyatomic ions are named according to their own naming convention – Ex. Li3PO4 is called Lithium Phosphate

Polyatomic Practice

• Ca+2 + PO4-3

• Mg + ClO4

 • Cu+1 + SO4

• Aluminum Hydroxide

• Iron (II) + Permanganate

Practice  Hydroxide,

OH-1

Nitrate, NO3

-1

Carbonate, CO3

-2

 

Sulfate, SO4

-2

Sodium, Na+1

 Magnesium, Mg+2

 Aluminum, Al+3

 Ammonium, NH4

+1

 

  Hydroxide, OH-1

Nitrate, NO3

-1

Carbonate, CO3

-2

 

Sulfate, SO4

-2

Sodium, Na+1

 

NaOH NaNO3 Na2CO3 Na2SO4

Magnesium, Mg+2

 

Mg(OH)2 Mg(NO3)2 MgCO3 MgSO4

Aluminum, Al+3

 

Al(OH)3 Al(NO3)3 Al2(CO3)3 Al2(SO4)3

Ammonium, NH4

+1

 

NH4OH NH4NO3 (NH4)2CO3 (NH4)2SO4

Practice• 1. Do the “Polyatomic Naming”

sheet found on Haiku.• 2. IF more time remains, do another

practice sheet from “Ionic Bonding” block on Haiku

Covlaent Bonding

• Covalent bonds occur between two or more non-metals.

• Valence electrons are shared to complete atoms outer shells.

Review: Ionic bonds occur between metals and non-metals.

Naming Covalent Compounds

• CO2

• CO

• H2O

Forming Covalent Bonds

• Dot and Cross Structures & Line structures

• Hydrogen + Hydrogen   • Hydrogen + Oxygen

• Bromine + Bromine

• Oxygen + Oxygen   

• Carbon + Oxygen

Building Covalent Compounds

• Build each covalent compound on the half sheet.

• Draw a color coded 3-D picture of the actual compound in your notebook.

• Draw a dot and cross structure for each compound beneath your drawing.

Modeling Lab Instructions

• There should be no empty holes in your atoms

• There should be no empty bonds in your compounds

• You cannot build rings of 3 or 4 atoms

Materials Key

• Carbon = Black• Hydrogen = White• Oxygen = Red• Halogens= Green• Nitrogen = Blue (ignore one

hole)• Bonds = Gray Tubes

• Describe how a molecule of ammonia (NH3) is made. Include a description of how each covalent bond is formed.

Giant Structures

• To finish out our study of Covalent Compounds, read about:– Giant Covalent Structures (pg. 60 - 61)– Simple Molecular Structures (pg. 56 -

57)

• How does the structure of a compound or molecule affect its properties?

Ionic vs Covalent Compounds

• What are the differences in the properties of ionic vs. covalent compounds?

• Read pg. 58 - 59

IN:

Work on these problems as I check off your homework:

What is wrong with these formulas?• Zn+2 + O-2 Zn2O2

• NH4+ + NO3

- NH3NO4

• Fe+3 + CO3-2 Fe2CO33

Chemical Equations

• Reactants products

Na2SO4 (aq) + CaCl2 (aq) CaSO4 (s) + 2NaCl (aq)

• The state of each reactant and product can be shown with a small symbol in parenthesis at the end of each formula (see above).– s for solid, l for liquid, g for gas, and aq if

the compound is an aqueous solution

Writing Chemical Equations

• Lead (II) nitrate solution reacts with potassium iodide solution to form lead (II) iodide solid and potassium nitrate solution.

• Copper metal reacts with oxygen gas (O2) to form copper (II) oxide.

Writing Chemical Equations

• Iron metal reacts with water to form iron (III) oxide solid and hydrogen gas (H2).

• magnesium hydroxide solution + carbon dioxide

water + solid magnesium carbonate

Balancing Chemical Equations

• When a chemical reaction happens bonds are broken, elements get rearranged, and new compounds are formed.

• The Law of Conservation of Matter tells us matter (or mass) cannot be created or destroyed!– The number of atoms of each type is the

same in both the reactants and products!

Demo

• Baking Soda & Vinegar

Balancing Equations• Step 1: Take an atom inventory • *List the type and number of each atom

on both sides of the chemical equation • H2CO3

• Ba(OH)2

• C3H8

 • NaC2H3O2

 • Al(NO2)3

• Step 2: Law of Conservation of Mass

*We must have the same number of atoms of each type on both sides*Use Coefficients to balance

~Example: 2NH3

H2 + O2 H2O

• FeS + HCl FeCl2 + H2S

• Fe2O3 + H2 Fe + H2O

• P + O2 P2O5

Homework

• Work through the practice problems on the Balancing Equations practice sheet. (Download from Haiku).– Show your atom inventory for every

problem!

• Do the “Writing and Balancing Equations WS” (Find on Haiku).