Post on 24-Dec-2015
ATOMShttps://www.youtube.com/watch?v=joOYgeqMJwU
ATOMS
Elements are composed of only one type of atom
Contain a nucleus which contain protons and neutrons
The force that hold two atoms together is a chemical bond.
Two or more atoms that are bonded together form a molecule.
Some are made up of only one type of atom but most are made up of two or more different types of atoms bonded together.
Electrons
Negatively charged
Orbit around the center of the atoms in orbits/shells called an electronic cloud
The farther from the center, the _______ energy it has
Gain and lose energy by moving between energy levels
In the nucleus of an atomPROTONS:
Positively charged and have a mass of 1The number of protons in an atoms nucleus determines what element it isThe amount of positive charge on a proton is equal to the amount of negative charge on an electron
NEUTRONS:Have no chargeMass of 1
Particle Name Location Charge Mass
Electron Orbitals -1 ~0Proton Nucleus +1 1
Neutron Nucleus No Charge 1
Atomic Number
Every atom of the same element has the same number of protons
It is the number of protons an element has which determines what element it is.
Mass Number = the total mass of an atom
It is the same as the number of protons & neutrons of the element.
One can calculate the number of neutrons an atom has by subtracting the atomic number (# protons) from the mass number.
Mass number CAN change without changing the identity of the element
Isotopes
Not all atoms of the same element have the same number of neutrons
Atoms of the same element that have different number of neutrons are called isotopes
Finding #’s
Number of Protons = Atomic Number
Number of Electrons = Number of Protons = Atomic Number
Number of Neutrons = Mass Number - Atomic Number
Periodic Table Notation:
Chemical elements are represented on the periodic table using the following format.
The letter is an abbreviation of Element NameAtomic Number Mass number.
Structure
Vertical columns are called groups or families
Numbered 1-18
Elements in each group have similar properties
Different elements with the same number of electrons in their outer energy level have similar chemical properties
Use a dot diagram to represent electrons in the outer energy level
StructureHorizontal rows are called periods
Look at the step lineAll elements to the left except hydrogen are metals
The elements to the right of the line are classified as nonmentals
Elements right next to the line are metalloids because they have properties of both metals and non mentals
http://ritter.tea.state.tx.us/student.assessment/resources/online/2009/taks_g11_science/images/chart2.gif
Interactions of matter: Atoms interact through the process of chemical bonding.
Process is determined by the number of electrons found in the outermost energy level of an atom.Involves the transfer & sharing of electrons between atoms.
Matter has a variety of characteristics or properties that can differ.
They fall into 2 different groups used to identify, describe and classify matter:
1. Physical
2. Chemical
A physical property can be observed without changing the substance into something else.
Odor
Taste
Hardness
Texture
Color
Temperature at which a solid melts or liquid boils
Whether its solid, liquid or gas
Physical Properties
A compound is a substance made of two or more elements chemically combined in a set ratio or proportion.
Examples: Carbon Dioxide gas is a compound made up of Carbon and Oxygen. Water is a compound made up of oxygen and hydrogen.
When elements are combined to make a compound, the new substance has properties different from those of the original elements.
Example: table sugar is made up of 3 elements- Carbon, Oxygen and Hydrogen.
Carbon=found in charcoal
Oxygen/hydrogen=colorless gases
Do sugar crystals resemble them?
Most matter occurs in mixtures.
A mixture is made from two or more substances (elements or compounds) that are in the same place but are NOT chemically combined.
Mixtures differ from compounds in 2 ways:
1. The substances in a mixture keep their individual properties.
2. The parts of a mixture are not necessarily present in set ratios.
Example: soil has particles of sand, tiny bits of clay, and pieces of decaying plants.
If you were to grab 2 handfuls of soil would they be made up of the same amount of clay, sand, and decaying plant matter?
Which is a mixture and which is a compound?
Chex mix
Table salt
Water
Muddy water
Carbon dioxide
Checkpoint
A chemical property is observed when a substance interacts with another substance.
Burning or flammability
Rusting
Tarnishing
Whether an object will explode
Chemical Properties
Two major groups of elements
Found on the periodic tableMetals are located to the left of the zigzag line
Nonmetals are located to the right of the zigzag line
Physical Properties of
MetalsHave Luster -shiny
Are Conductors -heat and electricity move through them easily
Malleable – Can be hammered into a different shape
Ductile – Can be drawn into a wire
High Density – Heavy for their size
Metals are solid, except for mercury
Alkali Metals
Group 1 on the periodic table
Shiny, malleable and ductile
Good conductors of heat and electricity
Highly reactive metals
Physical Properties of NonMetals
Dull – not shiny
Nonconductors – heat and electricity do not move through easily
Brittle – break easily
Most nonmetals are gases at room temperature
Metalloids
Both metal and non metal
May conduct electricity better than many nonmetals but not as well as some metals
SolutionsTwo (or more) substances mixed so thoroughly that neither can be observed in its original form.
Homogenous mixture, in which the particles of the mixing substances are evenly distributed throughout
1) Salt water 2) Syrup (sugar in water) 3) Vinegar (acetic acid in water)4) Shampoo (various soaps and surfactants dissolved in water)
5) Oxygen
6) Brass
Solute vs Solvent
The substance being dissolved is the solute
The substance that dissolves the solute is the solvent
How Do you Increase Rate of
Dissolving?For most solids
Increase temperatureStirShakeBreak solute into smaller pieces
SolubilityDifferent solutes dissolve at different temperatures
Solubility: the maximum number of grams of the substance that will dissolve in 100g of solvent at a certain temperature
Saturated solution: a solution that has dissolved all the solute it normally can hold at a given temperature
Oversaturated solution: any solution that can dissolve more solute at a given temperature
Supersaturated: Contains more solute than a saturated one has at that temperature. Unstable solution