atoms and their interactions
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Atoms and Their Interactions. 6.1. Elements. Elements A substance that can not be broken down into simpler chemical substances The Periodic Table lists all known elements. Atoms: The Building Blocks of Elements. Atom - PowerPoint PPT PresentationTRANSCRIPT
Atoms and Their Interactions
6.1
Elements
• Elements– A substance that can not be broken down into
simpler chemical substances– The Periodic Table lists all known elements
Atoms: The Building Blocks of Elements
• Atom– Smallest particle of an element that has the
characteristics of that element• Structure of an Atom– Nucleus
• Protons (Positive)• Neutrons (Neutral)
– Energy levels (outside of the nucleus)
• Electrons (Negative)
How come atoms do NOT have a charge?
In an atom, the number of electrons equals the number of protons.
So the number of positive and negative charges balance out, giving the atom a charge of 0.
Fill in the following chart:Particle Location Charge Symbol
Electron outside of nucleusIn energy levels
negative e-
ProtonInside the nucleus positive p+
NeutronInside the nucleus neutral n0
Energy Levels• First energy level
– 2 electrons• Second energy level
– 8 electrons• Third energy level
– 18 electronsRules for filling in energy levels!• The first energy level has to be FULL before electrons can go
into the 2nd energy level• The 1st and the 2nd energy level has to be FULL before
electrons can go into the 3rd energy level
Compounds
• Compounds are substances made of 2 or more elements that form a molecule (2 or more atoms together).
• Examples of common compounds:– Table Salt - NaCl– Oxygen gas – O2
– Water – H2O
Properties of Compounds• Compounds have BONDS between the atoms
• It is difficult to separate the parts of a compound
• Compounds have chemical formulas to tell you what elements are found in the compound and how many atoms of each element are present.– The chemical formula for water is H2O. There are two atoms
of hydrogen and one of oxygen.
Ionic Vs. Covalent Bonds
Ionic Bonds• Form when electrons are exchanged between
atoms.
Covalent Bonds• Form when electrons are shared between
atoms.
Both types of bonds result in all atoms having a full outer energy level.
Chemical Reactions
• Chemical reactions happen when bonds are formed or broken and recombine to form new compounds
• All chemical reactions that occur within an organism are referred to as that organism’s metabolism.
Mixtures
• Mixtures are combinations of 2 or more pure substances or compounds
• Some common mixtures:– Iced Tea– Dirt– Paint
Properties of Mixtures
• There are NO BONDS holding mixtures together
• Mixtures can often be separated
• Mixtures can occur in any proportions and DO NOT HAVE A SET FORMULA and can use different components
SolutionsSolution – mixture of one or more substances
uniformly distributed in another substance.
Can be solid, liquid, gas
ex. Plasma (liquid) brass (solid) copper and zinc soda (liquid/gas) water and CO2
Acids & BasesThe Homeostasis of living things depends on the
degree of acidity (acid) and alkalinity (base) in certain areas
Acids & BasesAcids= any substance that forms hydrogen (H+)
in water. Alkalinity (a/k/a basic solution)= any substance
that forms hydroxide ions (OH-) in water
Acids- pH < 7- Sour taste- Corrosive on metals- Burns skin
• Ex. Orange juice, • vinegar, sulfuric acid
*Homeostasis relevance- your stomach must have a certain acidity
to function properly
Bases-pH > 7- Tastes bitter- Slippery- Irritate the skin
- Ex. NaOH
- Homeostasis relevance- - your small intestine needs a
certain alkalinity (basic) to function properly
pH Scale- Tells you how acidic
or basic something is- Ranges 0-14
- 7 = neutral- above 7 = base - below 7 = acid
- Ten fold system- Measure pH with
litmus paper