CHM-131-160 Unit Two

Chemistry
The study of matter and explanation of its properties.
How many elements recognized on the periodic table are there?
119
What are elements made up of?
atoms
Is the shape of solids fixed or not fixed?
fixed
Is the shape of liquids fixed or not fixed?
not fixed
Is the shape of gases fixed or not fixed?
not fixed
Is the volume of solids fixed or not fixed?
fixed
Is the volume of liquids fixed or not fixed?
fixed
Is the volume of gases fixed or not fixed?
not fixed
Are solids compressible?
no
Are liquids compressible?
no
Are gases compressible?
yes
Describe the proximity of atoms or molecules of solids?
They are very close together and are ridigly fixed in space.
Describe the proximity of atoms or molecules of liquids.
They are close together but are still able to flow around each other.
Describe the proximity of atoms or molecules of gases.
They are not close and constantly collide with each other. They move very fast.
What is a physical change?
A physical change occurs when the physical form is changed, but the identity is not.
What is a chemical change?
A chemical change occurs when the identity of the substance is changed.
What are several examples of physical changes?
melting, freezing, boiling…
What are several examples of a chemical change?
combusting, decomposing, oxidating, precipitating…
What two types of physical properties exist?
intensive and extensive
What are intensive properties?

They do not depend on the amount of the substance.

e.g. density, temperature, boiling point, freezing point, melting point…

What are extensive properties?

Extensive properties do depend on the amount of the substance.

e.g. mass, volume, and heat (the amount that is required to raise the temperature varies depending on how much of the sustance there is)

Pure Substances
Matter with fixed composition and distinct properties. IT CANNOT BE SEPARATED MY ANY PHYSICAL MEANS.
Elements
A pure substance that is a fundamental, basic unit and are composed of the same types of atoms.
Compounds
Substances that are composed of more than one type of atom and have a fixed ratio of each element.
Mixtures
Two or more substances combined physically.
Homogeneous Compounds
Compounds that are uniformly mixed.
Heterogeneous Compounds
Compounds whose substances are not evenly distributed throughout.
What are the two types of compound?
Molecular and ionic.
What are the two types of mixtures?
Homogeneous or heterogeneous.
Dalton’s Atomic Theory

  1. Elements are composed of tiny individual particles called atoms.
  2. Atoms of the same element are identical.
  3. A compound forms when atoms from two or more elements bond together chemically in a fixed ratio.
  4. Atoms combine with simple whole number ratios.
  5. Atoms of two elements may combine in different ratios to form more than one compound.

What is not included in the Dalton’s Atomic Theory?
Nothing about atomic particles or anything inside the atom.
Law of Constant Composition
In a given compound the relative numbers and kinds of atoms are fixed.
Law of Constant Proportions
If two elements A & B combine to form more than one compound then, the mass of B taht combines with A is a ratio of small whole numbers.
What does the atom consist of?
protons, neutrons, and electrons
What particles are in the nucleus of the atom?
protons and neutrons
What is the charge and mass of the proton?

Charge: +1

Mass: 1

What is the charge and mass of the neutron?

Charge: none

Mass: 1

What is the charge and mass of the electron?

Charge: -1

Mass: negligible

What is the atomic number?

This number is how we identify different elements. It is also the number or both the protons and electrons in the neutral state of the atom of the element.

It is represented by a Z.

What is the atomic mass or mass number?

This is the mass of the proton and the neutron of the atom of the element. 

It is represented by an A.

Isotopes
These are atoms of the same element that differ from each other in the number of neutrons and subsequently mass.
The rows of the periodic table are called what?
periods
The columns of the periodic table are called what?
groups or families
IA
alkali metals
IIA
alkaline earth metals
VIA
chalcogens
VIIA
halogens
VIIIA
noble gases
IA-VIIIA
main or representative group
IB-VIIIB
transition metals
List the properties of metals.

Lusterous and shiny.

Malleable.

Ductile.

Conductible.

List the properties of non-metals.

Dull / multicolored.

Insulators.

Hard and brittle.

What are the 7 diatomic molecules?
H2, N2, O2, F2, Cl2, Br2, I2
What are the colors of the three different states on the periodic table?

gases: red

liquids: blue

solids: black

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