Chapter 2 Chapter 2

MatterMatter

AtomsAtomsSection 2-1 pg. 38 ques. 1-Section 2-1 pg. 38 ques. 1-77 What are atoms?What are atoms?

--AtomsAtoms are the building blocks of are the building blocks of mattermatter..

So, what is matter?So, what is matter?--Matter is anything that has a mass and takes up space.Matter is anything that has a mass and takes up space.- Matter surrounds us, and could take the form of solid, liquid Matter surrounds us, and could take the form of solid, liquid

or gas.or gas.

- What are some examples of matter?What are some examples of matter?- RocksRocks- DesksDesks- AirAir- WaterWater

Atoms (continued)Atoms (continued)

Is fire matter?Is fire matter?

No.No.

What about light?What about light?

No.No.

Neither one of these things is matter Neither one of these things is matter because they don’t take up any space.because they don’t take up any space.

Atoms (continued)Atoms (continued) Is all matter visible?Is all matter visible?- No. Air is matter as well as other colorless No. Air is matter as well as other colorless

gasses like butane, or propane.gasses like butane, or propane.- What causes matter to take these various forms What causes matter to take these various forms

and shapes? and shapes? - Its all depends on the way their atoms are put Its all depends on the way their atoms are put

together and also the shape that their atoms together and also the shape that their atoms take on.take on.

- In your body has several types of atoms that In your body has several types of atoms that combine in different ways. These atoms form combine in different ways. These atoms form proteins, DNA, tissues and other things that proteins, DNA, tissues and other things that makes you a person.makes you a person.

Also, many other objects you see around Also, many other objects you see around you are composed of many different types you are composed of many different types of atoms.of atoms.

However thee are things that are only However thee are things that are only made up of one type of atom. These made up of one type of atom. These things are called the things are called the elements.elements.

Elements are substances that are made of Elements are substances that are made of only one type of atom and cannot be only one type of atom and cannot be broken down into simpler substances by broken down into simpler substances by ordinary chemical means.ordinary chemical means.

MineralsMinerals Along with elements combining to make up Along with elements combining to make up

things you see everyday, they also make up things you see everyday, they also make up the the MineralsMinerals that compose the Earths crust. that compose the Earths crust.

MineralsMinerals are usually combinations of atoms are usually combinations of atoms that occur naturally in a crystal solid form.that occur naturally in a crystal solid form.

However some minerals are only composed However some minerals are only composed of element and they are called of element and they are called native native elementselements..

- Examples of native elements are Copper - Examples of native elements are Copper and Silver. What things do you know of that and Silver. What things do you know of that are made of these native elements.are made of these native elements.

The Atomic ModelThe Atomic Model

If you cant see atoms, then how are we able If you cant see atoms, then how are we able to study them.to study them.

- We use something called an We use something called an atomic modelatomic model..

- All atoms of an element contain the same All atoms of an element contain the same type of atom. Ex: All atoms of the element type of atom. Ex: All atoms of the element Carbon are carbon atoms.Carbon are carbon atoms.

The Atomic ModelThe Atomic Model Every atom is composed of Every atom is composed of

three different three different particlesparticles..1) 1) ProtonsProtons- which are positively - which are positively

charged particles, located charged particles, located inside the nucleus of the inside the nucleus of the atom.atom.

2) 2) NeutronsNeutrons- which is a particle - which is a particle with no charge. Also located with no charge. Also located inside the nucleus.inside the nucleus.

- Because there is no Because there is no negative charges inside negative charges inside the nucleus to counter act the nucleus to counter act the positively charged the positively charged protons, the overall protons, the overall charge of the nucleus is charge of the nucleus is positive.positive.

3) 3) ElectronsElectrons- - These are particles These are particles that have a negative charge that have a negative charge and are found outside the and are found outside the nucleus.nucleus.

ElectronsElectrons Electrons have some special features that Electrons have some special features that

we need to look at.we need to look at.- First, we need to know that they are grouped First, we need to know that they are grouped

into energy levels, and that each level into energy levels, and that each level contains a specific number of electrons.contains a specific number of electrons.

- Second, electrons float in a kind of cloud Second, electrons float in a kind of cloud around the nucleus of the atom.around the nucleus of the atom.

Try to think of it like a beehive. The hive is Try to think of it like a beehive. The hive is the nucleus and all the swarming bees the nucleus and all the swarming bees around the hive are the electronsaround the hive are the electrons..

Counting Atomic Counting Atomic ParticlesParticles Not every atom has the same amount of atomic Not every atom has the same amount of atomic

particles (protons, neutrons, and electrons). So particles (protons, neutrons, and electrons). So how do we count them.how do we count them.

We use a table called the Periodic Table of We use a table called the Periodic Table of Elements.Elements.

Counting ProtonsCounting Protons We are able to count the We are able to count the

number of protons in an number of protons in an atom by using the atom by using the Atomic Atomic NumberNumber of an element. of an element.

The number of Protons in The number of Protons in an atom of an element is an atom of an element is always always equalequal to the to the Atomic Number.Atomic Number.

Carbons Atomic Number Carbons Atomic Number is 6 therefore an atom of is 6 therefore an atom of Carbon has six Protons.Carbon has six Protons.

How to count electronsHow to count electrons In a neutral atom, the number of electrons will In a neutral atom, the number of electrons will

always be equal to the number of protons.always be equal to the number of protons. However, some atoms can lose or gain However, some atoms can lose or gain

electrons and continue to remain the same electrons and continue to remain the same element..element..

If you lose an electron the overall charge of If you lose an electron the overall charge of the atom becomes positive. the atom becomes positive.

If you lose a proton the overall charge of the If you lose a proton the overall charge of the atom becomes negative.atom becomes negative.

How to count NeutronsHow to count Neutrons We count the amount We count the amount

of neutrons in an of neutrons in an atom by using the atom by using the elements elements mass mass number.number.

Mass NumberMass Number- - equals the number of equals the number of protons plus the protons plus the number of neutrons.number of neutrons.

So to find the # of So to find the # of neutrons, subtract the neutrons, subtract the atomic number from atomic number from the mass number.the mass number.

IsotopesIsotopes Atoms of the same element that have different Atoms of the same element that have different

number of neutrons is called an number of neutrons is called an isotopeisotope..

Ex: Normal carbon C12 has 6P 6N & 6E.Ex: Normal carbon C12 has 6P 6N & 6E.

An isotope of Carbon C14 has 6P 8N & 6EAn isotope of Carbon C14 has 6P 8N & 6E

Isotopes can sometimes be radioactive.Isotopes can sometimes be radioactive.- We use these radioactive isotopes to treat - We use these radioactive isotopes to treat

cancer, date rocks and label proteins.cancer, date rocks and label proteins.

Anatomical InteractionsAnatomical InteractionsSection 2-2 H.W. pg. 44 ques. 1-5Section 2-2 H.W. pg. 44 ques. 1-5

So we know that substances that only have So we know that substances that only have one kind of atom is called an element.one kind of atom is called an element.

There are 90 different elements that occur There are 90 different elements that occur naturally on Earth, meaning they are not naturally on Earth, meaning they are not man made. man made.

So with only 90 elements, how is it that so So with only 90 elements, how is it that so many different things on Earth are made?many different things on Earth are made?

They are made by the infinite number of They are made by the infinite number of possible combinations that the elements possible combinations that the elements can form.can form.

Anatomical InteractionsAnatomical Interactions These combinations that are made when These combinations that are made when

the atoms of more than one element the atoms of more than one element combine are called combine are called compoundscompounds..

Water is a compound made of what 2 Water is a compound made of what 2 elements?elements?

H 2 0. This way of writing water is called H 2 0. This way of writing water is called its chemical formula. its chemical formula.

NaCl is sodium chloride. Does anyone NaCl is sodium chloride. Does anyone know what NaCl’s common name is?know what NaCl’s common name is?

Chemical PropertiesChemical Properties

A chemical property is a property that A chemical property is a property that describes a change that occurs when describes a change that occurs when one substance reacts with another.one substance reacts with another.

Ex: when electricity is passed through Ex: when electricity is passed through water, water breaks up into hydrogen gas water, water breaks up into hydrogen gas and oxygen gas. This is a chemical and oxygen gas. This is a chemical property of water.property of water.

BondingBonding Chemical bondsChemical bonds- are the forces that hold the - are the forces that hold the

atoms together in a compound. atoms together in a compound. These bonds form between the outermost These bonds form between the outermost

electrons of two or more different atoms.electrons of two or more different atoms. The outermost electron level of an atom can only The outermost electron level of an atom can only

have 8 electrons. If an atoms highest electron have 8 electrons. If an atoms highest electron level has fewer than 8 electrons it will interact level has fewer than 8 electrons it will interact with other electrons of a different atom to form a with other electrons of a different atom to form a compound.compound.

If an atoms outermost electron level is occupied If an atoms outermost electron level is occupied by 8 electrons than it will not readily react with by 8 electrons than it will not readily react with other atoms to form compounds.other atoms to form compounds.

Four types of bondsFour types of bonds

1)1) Covalent bonds- Covalent bonds- These occur when the These occur when the atoms of two different atoms of two different elements share elements share electrons.electrons.

- A group of atoms A group of atoms connected by covalent connected by covalent bonds is called a bonds is called a molecule.molecule.

- An example would be An example would be the covalent bonds the covalent bonds between Hydrogen and between Hydrogen and oxygen in a water oxygen in a water molecule.molecule.

Four types of bondsFour types of bonds2) 2) Ionic bonds-Ionic bonds- These occur when atoms of two These occur when atoms of two

or more elements exchange electrons.or more elements exchange electrons.- These bonds occur when an atom becomes These bonds occur when an atom becomes

either positively or negatively charged.either positively or negatively charged.- Atoms become positive or negative by losing or Atoms become positive or negative by losing or

gaining electrons. When that happens when call gaining electrons. When that happens when call themthem ions. ions.

- These ions are attracted to each other when These ions are attracted to each other when they have opposite charges.they have opposite charges.

- And when ions combine they form electrically And when ions combine they form electrically neutral compounds.neutral compounds.

- An example is NaCl. Na has a positive charge An example is NaCl. Na has a positive charge and Cl has a negative charge, so they join to and Cl has a negative charge, so they join to make a neutral NaCl moleculemake a neutral NaCl molecule

Four types of bondsFour types of bonds3) 3) Hydrogen bonds-Hydrogen bonds- These bonds form without the These bonds form without the

interactions of electrons.interactions of electrons.

- These bonds make a molecule - These bonds make a molecule polarpolar, meaning that , meaning that the molecule has a partially positive end and a the molecule has a partially positive end and a partially negative end. partially negative end.

- An example would be the hydrogen bonds An example would be the hydrogen bonds between water molecules. The partially negative between water molecules. The partially negative end of a water molecule is attracted to the partially end of a water molecule is attracted to the partially positive end and allows two or more water positive end and allows two or more water molecules to bond.molecules to bond.

- These H-bonds are very weak and are broken These H-bonds are very weak and are broken easily.easily.

MixturesMixtures

A A mixturemixture is composed is composed of two or more of two or more substances that are not substances that are not chemically combined.chemically combined.

- Two types of Mixtures:Two types of Mixtures:1) 1) Heterogeneous Heterogeneous

mixture- mixture- the the components of this type components of this type of mixture are not mixed of mixture are not mixed evenly and each evenly and each component retains its component retains its own propertiesown properties..

MixturesMixtures

2) 2) Homogeneous Mixture- Homogeneous Mixture- These types of These types of mixtures are evenly mixed throughout. mixtures are evenly mixed throughout. And individual components cannot be And individual components cannot be seen.seen.

-They are also called solutions.-They are also called solutions.

An Example would be how salt dissolves in An Example would be how salt dissolves in water. water.

Separating Mixtures & Separating Mixtures & CompoundsCompounds

Componants of a compound or a mixture Componants of a compound or a mixture can be separated by either physical or can be separated by either physical or chemical means.chemical means.

If you boil a salt water mixture, the water If you boil a salt water mixture, the water will evaporate away and the salt will will evaporate away and the salt will remain in the glass. (Physical)remain in the glass. (Physical)

The components of a compound must be The components of a compound must be separated by chemical means.separated by chemical means.

Ex: HCL + CaCO3 --------Ex: HCL + CaCO3 -------- CO2 CO2

Properties of MatterProperties of MatterSection 2-3 H.W. Pg. 56Section 2-3 H.W. Pg. 56 ques. 1-18ques. 1-18

Physical PropertiesPhysical Properties- properties that you can - properties that you can observe without changing a substance into a observe without changing a substance into a new substance.new substance.

-Ex: -Ex: A physical property of you hair might be that A physical property of you hair might be that its red or brown, curly or straight.its red or brown, curly or straight.

One physical property that you would use to One physical property that you would use to describe matter would be describe matter would be densitydensity..

DensityDensity – is a measure of the mass of an object – is a measure of the mass of an object divided by its volume. The measurement used divided by its volume. The measurement used for density is g/cmfor density is g/cm3.3.

--So if 1cmSo if 1cm3 3 of water has a mass of about 1g this of water has a mass of about 1g this means its density is 1g/cmmeans its density is 1g/cm33

Properties of MatterProperties of Matter

If an object is more dense than water it If an object is more dense than water it will sink in water.will sink in water.

If an object is less dense than water it will If an object is less dense than water it will float.float.

Density problemDensity problemProblem: You want to find the density of a small cube. It Problem: You want to find the density of a small cube. It

measures 1cm x cm x 2cmmeasures 1cm x cm x 2cm and has a mass of 8g. What's the density of the cube.and has a mass of 8g. What's the density of the cube.What you knowWhat you know: : mass: m= 8gmass: m= 8g volume: v= 1cm x 1cm x 2cm= 2cmvolume: v= 1cm x 1cm x 2cm= 2cm33

Density: d= m/vDensity: d= m/vWhat you want to findWhat you want to find: : Density: dDensity: dHow to solveHow to solve: : If d=m/v just substitute the numbers you have for v and m into If d=m/v just substitute the numbers you have for v and m into

the equation.the equation.D=8g/2cmD=8g/2cm33

D= 4g/cmD= 4g/cm3 3

To check your answer multiply the your answer by the given To check your answer multiply the your answer by the given volume of 2cmvolume of 2cm3 3 and you get 8g.and you get 8g.

States of MatterStates of Matter There are four states of matter, solid, There are four states of matter, solid,

liquid, gas and plasma.liquid, gas and plasma.

1)1) SolidsSolids- solid matter occurs when particles - solid matter occurs when particles are in fixed positions relative to each other. are in fixed positions relative to each other. Here, individual particles vibrate but they Here, individual particles vibrate but they don’t switch positions with each other.don’t switch positions with each other.

- -

Solids take up a definite volume and have a Solids take up a definite volume and have a definite shape.definite shape.

States of MatterStates of Matter2)2) Liquids Liquids- particles in liquid form are attracted - particles in liquid form are attracted

to each other, but are not in fixed positions.to each other, but are not in fixed positions.

- The reason why liquid particles are not fixed The reason why liquid particles are not fixed is because of their energy. Liquid particles is because of their energy. Liquid particles have more energy than solid particles and have more energy than solid particles and causes them to move around and change causes them to move around and change positions with each other.positions with each other.

- The particles in a liquid will always change The particles in a liquid will always change position in order to fit the container that is position in order to fit the container that is holding them.holding them.

States of MatterStates of Matter3) 3) GasesGases- the particles that make up gases - the particles that make up gases

have enough energy to overcome any have enough energy to overcome any attractions between them. This allows them attractions between them. This allows them to move freely and independent of each to move freely and independent of each other.other.

- Unlike liquids and solids, gases spread out Unlike liquids and solids, gases spread out and fill whatever container they are placed in.and fill whatever container they are placed in.

Like a balloon.Like a balloon.

States of MatterStates of Matter4) 4) PlasmaPlasma- Plasma is the most common state - Plasma is the most common state

of matter in the universe. This state is of matter in the universe. This state is associated with high temperatures.associated with high temperatures.

- Plasma is composed of ions and electrons, Plasma is composed of ions and electrons, and forms when high temperatures cause and forms when high temperatures cause some electrons to escape the cloud its in some electrons to escape the cloud its in around the nucleus of an atom.around the nucleus of an atom.

Ex: Sun, Stars, and lightning bolts. Ex: Sun, Stars, and lightning bolts.

Changing the State of Changing the State of MatterMatter

Matter is changed from a liquid to a solid at its Matter is changed from a liquid to a solid at its freezing point.freezing point.

Matter is changed from a liquid to a gas at is Matter is changed from a liquid to a gas at is boiling point.boiling point.

The freezing point of water is 0 The freezing point of water is 0 °C and its °C and its boiling point is 100 °C.boiling point is 100 °C.

Water is the only substance on Earth that Water is the only substance on Earth that occurs naturally in all three states of matter.occurs naturally in all three states of matter.

Changing the State of Changing the State of MatterMatter

Changes is states occur due to and increase Changes is states occur due to and increase or decrease in energy. or decrease in energy.

If you increase energy you increase the If you increase energy you increase the movement of particles. Ex: Boiling Watermovement of particles. Ex: Boiling Water

This increase in energy causes heat which This increase in energy causes heat which melts an ice cube and evaporates the puddle melts an ice cube and evaporates the puddle left behind.left behind.

Pressure could also effect changes in state. A Pressure could also effect changes in state. A decrease in pressure will lower the boiling decrease in pressure will lower the boiling points of liquids.points of liquids.

When pressure increases solids melt faster.When pressure increases solids melt faster.

Changes in Physical Changes in Physical PropertiesProperties

When a molecule of water changes states its When a molecule of water changes states its chemical composition does not change. chemical composition does not change. Liquid, gas or solid water molecules are Liquid, gas or solid water molecules are always water molecules.always water molecules.

However waters physical properties do However waters physical properties do change. Ex: When water is frozen as ice it change. Ex: When water is frozen as ice it becomes less dense than liquid water. That’s becomes less dense than liquid water. That’s why ice cubes float in a glass of water.why ice cubes float in a glass of water.

Test on Chapter 2 in one Test on Chapter 2 in one week!!!!!!!week!!!!!!!