ATOMS

Objectives

What is an atom and its three subatomic parts?

What are the charges of the three subatomic parts?

How do you find atomic mass and the atomic number?

Compound vs. element?What is an isotope?

How small is an atom?

The basic unit of matter. the smallest unit.‘unable to be cut’Can it be seen?Is it living? 100 million atoms side by side is about the width of your pinkie!

What is an atom made of?3 subatomic particles

◦Proton ◦Neutron ◦Electron

ProtonPOSITIVE PROTON (+)Located inside the nucleusHas a positive charge and contributes to

the massMass - 1.00727638 AMU

Neutrons NEUTRAL NEUTRON

◦Located inside the nucleus◦Has no charge but contributes to the mass◦Mass- 1.0086649156 AMU

Electrons Negative Charge

◦Orbits around the nucleus and is in constant motion. ◦They are attracted to the positive charged nucleus. ◦There are the same amount of protons as electrons.◦Mass is too small to be included.◦Mass- 0.0005446623 AMU◦ (1/1836th the mass of a proton)

Periodic Table

Element- pure substance containing only one type of atom. We distinguish the

elements based on protons, neutrons, and electrons.

Compound

A substance formed by the chemical combination of 2 or more elements.

The physical and chemical properties of a compound and usually very different from the elements in which they are formed.

Sodium is a soft metal + poisonous chlorine = sodium chloride

+ =

compounds2 or more elementsWater = salt (sodium chloride) =

Atom = smallest unit of an elementMolecule = smallest unit of compound

What does it mean?

Atomic number= # of protons = # of electrons Atomic Mass= # of protons + number of

neutrons

Atomic mass

IsotopesIsotopes are atoms of the same element

with the same number of protons but different number of neutrons.

Some isotopes can give off radiationIsotopes are identified by their atomic

mass.

Isotopes

Helium-5 Atomic Mass = Atomic number (protons) = Number of neutrons =   Helium-6 Atomic Mass = Atomic number (protons) = Number of neutrons =

Helium-7 Atomic Mass = Atomic number (protons) = Number of neutrons = Helium-8 Atomic Mass = Atomic number (protons) = Number of neutrons =

BondsWhat is the difference between a covalent

bond and an ionic bond?What is an ion?What are valence electrons?

Chemical bonds

Ionic – electrons are transferred from one atom to the next.

Covalent- electrons are shared between atoms

Ionic bonds

Formed when one or more electrons are transferred and ions (charged atoms)are paired.

What is the charge of an electron?When sodium looses an electron it has a

positive charge. Opposite ions attract!

Valence electronsThe electrons in one atom that are able to form

bonds with another atom. The closer the atom is to having 8 valence

electrons , the more stable it is.

Where are the valence electrons?

Ionic BondsBonds between a metal and nonmetal.

Covalent BondElectrons are shared between atoms. 1 bond is when atoms share 2 electronsNonmetal with nonmetalNeither atom is strong enough to pull an

electron away from the other so they share.

Can an atom be broken?

http://www.youtube.com/watch?v=xyY4cWKPrSc

Water - 3,000,000,000,000,000,000,000 water

molecules in a single drop of water!

Properties of water1. Polarity2. Hydrogen bonds3. Cohesion4. Adhesion

http://www.youtube.com/watch?v=ivu4nlvD_90

Hydrogen bonds

The weak interaction between the slightly positive hydrogen and a negative atom (oxygen, fluorine, nitrogen)

Cohesion

Surface Tension

Adhesion