Biological Organization

“Biological Organization” How living things are organized

Early Greek Theories of Matter The theory of the 4 Elements (credited to Empedocles B.C.) According to the Greek theory of matter everything in the universe is made of four basic elements: Fire Air Water Earth

Empedocles – Theory of 4 Elements

Democritus 460 B.C. – 370 B.C. Democritus was a Greek Scientist and created the 1 st atomic theory Democritus was a Greek Scientist and created the 1 st atomic theory He hypothesized that all matter is composed of tiny units, called atoma. He hypothesized that all matter is composed of tiny units, called atoma. Considered to be the “father of modern science” Considered to be the “father of modern science”

Atoms “Atom” in Greek means that which can’t be cut or divided “Atom” in Greek means that which can’t be cut or divided Atoms are the smallest building blocks of all life Atoms are the smallest building blocks of all life

Atoms Atoms are made of smaller units called subatomic particles Atoms are made of smaller units called subatomic particles The three subatomic particles are: The three subatomic particles are: Protons (nucleus) + Protons (nucleus) + Neutrons (nucleus) 0 Neutrons (nucleus) 0 Electrons (electron cloud) - Electrons (electron cloud) -

HELIUM ATOM + N N proton electron neutron Shell Parts of an atom

HISTORY OF THE ATOM John Dalton: Revised the atomic theory to suggest that all matter was made up of tiny spheres that were able to bounce around with perfect elasticity and called them ATOMS

HISTORY OF THE ATOM 1913 Niels Bohr Bohr further refined the atomic theory by adding that the electrons were in orbits. Rather like planets orbiting the sun. With each orbit only able to contain a set number of electrons.

Elements Many atoms of the same kind form elements Many atoms of the same kind form elements

Periodic Table Although there were precursors, the current periodic table is credited to Russian chemist Dmitri Mendeleev in Although there were precursors, the current periodic table is credited to Russian chemist Dmitri Mendeleev in 1869.Dmitri MendeleevDmitri Mendeleev

Periodic Table Podcast oVGk oVGk oVGk oVGk

Atomic Number The periodic table is arranged by atomic number The periodic table is arranged by atomic number Atomic Number is the number of protons in the nucleus (same as # of e-) Atomic Number is the number of protons in the nucleus (same as # of e-)

How can the number of protons be determined Atomic Number

How can the number of neutrons be found? ATOMIC MASS

The periodic table is also… Organized according to states of matterOrganized according to states of matter

ATOMIC STRUCTURE Electrons are arranged in Energy Levels or or Shells around the nucleus of an atom. first shell  a maximum of 2 electrons second shell  a maximum of 8 e- third shell  a maximum of 18 e-

Molecules 2 or more atoms bonded together 2 or more atoms bonded together Ex. 2 atoms of oxygen make one oxygen molecule Ex. 2 atoms of oxygen make one oxygen molecule

Compounds A molecule that contains at least 2 different elements A molecule that contains at least 2 different elements Ex. 2 hydrogen atoms and one oxygen atom create one molecule of H20 (water) Ex. 2 hydrogen atoms and one oxygen atom create one molecule of H20 (water)

How do atoms get “stuck” together? Bonds! Bonds! To get a stable outer shell of electrons, atoms either give away, take on, or share electrons. To get a stable outer shell of electrons, atoms either give away, take on, or share electrons.

3 Types of Bonds Ionic Ionic Covalent Covalent Metallic Metallic

Ionic Bonds Formed between the transfer of electrons Formed between the transfer of electrons Produce charged ions all states. Conductors and have high melting point. Produce charged ions all states. Conductors and have high melting point. Examples; NaCl, CaCl 2, K 2 O Examples; NaCl, CaCl 2, K 2 O

Ions an atom or molecule with a net (overall) electric charge due to the loss or gain of one or more electrons

Covalent Bonds Formed by the sharing of electrons Formed by the sharing of electrons Examples; O 2, CO 2, C 2 H 6, H 2 O Examples; O 2, CO 2, C 2 H 6, H 2 O

Metallic Bonds Bond found in metals, very strong Bond found in metals, very strong Good conductors at all states, lustrous, very high melting points Good conductors at all states, lustrous, very high melting points Examples; Na, Fe, Al, Au, Co Examples; Na, Fe, Al, Au, Co

ATOMIC STRUCTURE The structure and bonds of atoms, molecules and compounds can be represented by electron dot diagrams & Lewis Structures Valence Electrons: The outermost electrons in orbit that participate in the chemical bonds

Electron dot diagram show valence electrons of one element

Make an electron dot diagram for: -oxygen -hydrogen

Lewis Structures show bonding of molecules Ex. Water

Subscripts in a chemical formula tell us the number of atoms of each element represented Ex. H ₂ O How many atoms of Hydrogen? Oxygen? Draw a Lewis Structure to represent one molecule of water.

Lise Meitner Lise Meitner, ( ) was an Austrian, physicist who worked on radioactivity and nuclear physics. Meitner was part of the team that discovered nuclear fission (splitting an atom), an achievement for which her colleague Otto Hahn was awarded the Nobel Prize. Meitner is often mentioned as one of the most glaring examples of women's scientific achievement overlooked by the Nobel committee

Marie Curie Marie Curie ( ) was a chemist, famous for her pioneering research on radioactivity. She was the first woman to win a Nobel Prize

Antoine Lavoisier Antoine Lavoisier (1743 – 1794) Antoine Lavoisier In 1778, Antoine Lavoisier, a French scientist, conducted many experiments air and theorized that the gas made some substances acidic. He named this gas oxygen, from the Greek words that loosely translate as "acid maker". While Lavoisier’s theory about oxygen and acids proved incorrect, his name stuck. In 1778, Antoine Lavoisier, a French scientist, conducted many experiments air and theorized that the gas made some substances acidic. He named this gas oxygen, from the Greek words that loosely translate as "acid maker". While Lavoisier’s theory about oxygen and acids proved incorrect, his name stuck.Antoine LavoisierAntoine Lavoisier

Lavoisier knew that acids react with some metals to release another strange and highly flammable gas called phlogiston. Lavoisier mixed the two gases, phlogiston and the newly renamed oxygen, in a closed glass container and inserted a match. He saw that phlogiston immediately burned in the presence of oxygen and afterwards he observed droplets of water on the glass container.

After careful testing, Lavoisier realized that the water was formed by the reaction of phlogiston and oxygen, and so he renamed phlogiston hydrogen, from the Greek words for "water maker". From these observations, Lavoisier established the Law of Conservation of Mass.

Law of Conservation of Mass Mass is not lost or gained during a chemical reaction. Mass is not lost or gained during a chemical reaction. video/108987/83548/Antoine-Lavoisier-discovered-the-chemical- explanation-for-fire video/108987/83548/Antoine-Lavoisier-discovered-the-chemical- explanation-for-fire

Chemical Equations Represents chemical changes

A chemical equation is a symbolic representation of a chemical reaction.

Equation Example: The burning of methane gas in oxygen is: CH O 2 → CO H 2 O C = 1 H = 4 O = 4 This is a balanced equation

Reading Chemical Equations The two sides of the equation are separated by an arrow. The two sides of the equation are separated by an arrow. –The combination of chemicals before the reaction are on the left side of the arrow –The right side indicates the combination of chemicals after the reaction.

Subscript Shows the number of atoms of each element in a molecule Shows the number of atoms of each element in a molecule H 2 SO 4 H 2 SO 4 – Elements Hydrogen; 2 atoms Hydrogen; 2 atoms Sulfur: 1 atom Sulfur: 1 atom Oxygen: 4 atoms Oxygen: 4 atoms – 7 atoms total Subscript

Coefficients Represents # of molecules Represents # of molecules 2H 2 SO 4 – 2 molecules of Sulfuric Acid 2H 2 SO 4 – 2 molecules of Sulfuric Acid –A coefficient is distributed to ALL elements in a compound 2 – H 2 (for a total of 4 H atoms) 2 – H 2 (for a total of 4 H atoms) 2 – S (for a total of 2 S atoms) 2 – S (for a total of 2 S atoms) 2 – O 4 (for a total of 8 O atoms) 2 – O 4 (for a total of 8 O atoms) CH O 2 → CO H 2 O Coefficient

For Example: In this reaction, sodium (Na) and oxygen (O 2 ) react to make a single molecule, Na 2 O In this reaction, sodium (Na) and oxygen (O 2 ) react to make a single molecule, Na 2 O Na + O 2 → Na 2 O

You can change a coefficient….. You can’t change a subscript

Balancing Equations The Law of Conservation of Mass states that in a chemical reaction, the quantity or amount of each element does not change. The Law of Conservation of Mass states that in a chemical reaction, the quantity or amount of each element does not change. This means that each side of the equation must represent the same quantity of each element; in other words have the same number of each kind of atom. This means that each side of the equation must represent the same quantity of each element; in other words have the same number of each kind of atom.

Balancing Equations Na + O 2 → Na 2 O In order for this equation to be balanced, there must be equal amount of Na on the left hand side and on the right hand side. Right now, there is 1 Na atom on the left but 2 Na atoms on the right. We solve this problem by putting a 2 in front of the Na on the left hand side, Like this: 2Na + O 2 → Na 2 O

Balancing Equations 2Na + O 2 → Na 2 O There are 2 Na's on the left and 2 Na's on the right. But what about the O? We now must check to see if the O's are balanced on both sides of the equation. On the left hand side there are 2 O's and the right hand side only has one. This is still an unbalanced equation. To fix this we must put a 2 in front of the Na 2 O on the right hand side. Now our equation reads: 2Na + O 2 → 2Na 2 O

Balancing Equations 2Na + O 2 → 2Na 2 O Notice that the 2 on the right hand side is "distributed" to both the Na 2 and the O. Currently the left hand side of the equation has 2 Na's and 2O's. The right hand side has 4 Na's total and 2 O's. Again, this is a problem, there must be an equal amount of each chemical on both sides. To fix this let's add 2 more Na's on the left side. The equation will now look like this: 4Na + O 2 → 2Na 2 O

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