Post on 22-Dec-2015
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