REVIEW OF THE ATOM

Sub-atomic Particle

Where Found Charge

Proton Nucleus +1

Neutron Nucleus 0

Electron Around nucleus -1

Helium Atom - He

2 electrons

2 protons

2 neutrons

nucleus

He2

4.00

Helium

Definitions (refer to handout) Atom – small particles that make up everything around

us (matter). Element – If a substance is made up of only one type

of atom. Eg. Zinc, Oxygen, Copper. Compound – a substance that contains two or more

different elements that are chemically combined. Eg. Copper Sulphate, Water.

Mixture – a substance that contains two or more different substances that are not chemically combined.

Proton – a positive charged particle held within the nucleus of an atom.

Neutron – an uncharged particle held within the nucleus of an atom.

Electron – a negatively charged particle that is free to move around the nucleus.

The Parts of the Atom

ElectronElectron

OrbitOrbit

NeutronNeutron

ProtonProton

NucleusNucleus

Atomic Number – the number of protons in an atom. Mass Number – the number of protons and neutrons in

an atom. Atomic Mass – the average Mass Number of all the

different isotopes of an element. Isotope – when two atoms have the same number of

protons but a different number of neutrons (therefore a different mass number).

Ion – an element or a compound, which takes on a charge due a variation between the number of protons and electrons, it possesses. (cation +, anion -)

Ionic Charge – the charge of an atom. Eg. Oxygen contains 8 protons and 10 electrons, therefore 8 positive charges and 10 negative charges, i.e. 2- charge.

Definitions (refer to handout)

Parts of the Periodic Table

Hydrogen1

1.007

Name of the ELEMENT.

Atomic number of the element

Symbol for the element.

Atomic Mass of the element

H

Review of the Periodic Table

Lithium3

6.941

What is the symbol for Lithium?

_________

What is the atomic number of Lithium?

_________

How many protons does Lithium have?

_________

How many electrons does a neutral Lithium atom have?

__________

What is the atomic weight for Lithium?

_______________

Li

Li

3

3

6.941

3

Physical properties are properties which do not involve the substance turning into something else

Eg. appearance, texture, colour, odour, melting point, boiling point solubility,

Chemical properties are properties that substances show when they undergo changes to something else

Eg. Flammability Reactivity

Questions

1. What chemical property is shared by petrol, wood, kerosene and coal?

2. What are the physical properties of cement

3. Classify the following as physical / chemical properties Soluble Smooth Rusty Produces bubbles when acid added Round

FLAMABLE

HARD, not soluble (insoluble) in water, GREY, solid at room temp.

PhysicalPhysical

ChemicalChemical

Physical

Physical Changes

During a physical change the substance remains the same substance, but some of its properties may change

A physical change can be reversed Examples include, changes to;

Size Shape State (solid, liquid, gas) Ie: melting chocolate, freezing water…

Chemical Changes

In a chemical change, one or more new substances are formed

Chemical changes are the result of chemical reactions

Examples include; Production of gas Production of heat or light A permanent change in colour The formation of a precipitate (new solid) Ie: rusting iron

REVIEW

In this type of change the substance remains the same substance.

_________________

In this type of change the substance turns into a different substance

_________________

Physical Change

Chemical Change

IONS

Ions - are atoms or groups of atoms that have a positive or negative charge. Ions are formed when an atom gains or loses an electron.

The charge on an atom can only change by changing the number of electrons.

You can’t change protons

Ions-

+ = Zero (0) overall charge

+ ++ +

-+ =

-_______ overall charge

+ ++ +

-+ =

-_______ overall charge

-

+ ++ +

-

- -

--

IONS Metals tend to lose electrons becoming positive (+)

Non-Metals tend to gain electrons becoming negative (-)

Ions

Cations - are ions, which have a positive charge (due to losing electrons)

Anions - are ions, which have a negative charge (due to gaining electrons)

Polyatomic ions - are groups of atoms that have a charge and act as a unit. Eg. SO4

2- contains 1 Sulphur and 4 Oxygen atoms and carries a 2- charge.

Diatomic elements - are two atoms of the same element bonded together. Eg. H2, I2, Br2, Cl2, O2, N2, Hg2,

Cation or Anion?