Physical Science: Origin of Elements and Biomolecules

• Physical Science Final Examination, 2nd Term: 3rd Quarter

Topic Overview

Origin and Formation of Elements in the Universe

• Theories include the formation of the universe and phases of the Big Bang theory.
• Cosmic origin of elements and timeline of atomic theory
• Deals with atoms, ions, isotopes, atomic identity, nuclear reactions, and equations

Chemical Bonds, LEDS, and Molecular Polarity

• Focus is classification of matter and notable scientists.
• Details chemical bonding through Lewis Electron Dot Structure (LEDS), plus ionic and covalent bonds.
• Addresses molecular polarity

Intermolecular Forces

• Covers Intramolecular and Intermolecular Forces such as Ion-Dipole and Dipole-Dipole forces

Biomolecules

• Carbon is highlighted as the central atom, and includes monomers/polymers
• Dehydration and hydrolysis processes result in the formation of biomolecules.
• Addresses protein structure/function, carbohydrates (key features, mono/di/polysaccharides)
• Discusses nucleic acids (structure, DNA, RNA, functions) and lipids (ester linkage, structure, functions)

Collision Theory and Chemical Reactions

• Distinguishes between a chemical change and reaction, and discusses rates of chemical reactions.
• Reactants must be in proper orientation and possess a minimum amount of energy.
• Outlines factors affecting reaction rate like temperature, concentration, and pressure.

Lesson 1: Origin and Formation of Elements in the Universe

Theories on the Formation of the Universe

• Creation theory posits supernatural/divine beings created the world and all life.
• Multiverse theory proposes our universe is one of many, each with unique characteristics.
• Oscillating theory describes ongoing cycles of expansion/contraction

Steady State Theory

• States that the universe has always existed in a constant state, without a beginning or end
• It has since been disproven and is therefore invalid

Big Bang Theory

• Starts from single point (singularity), universe began with expansion, not explosion.
• Universe started from one point, termed Singularity
• Universe began with expansion, not explosion
• Edwin Hubble and Georges Lemaitre are attributed to big bang theory
• The Milky Way is not the only existing galaxy
• Galaxies are in constant motion, going away from each other

Phases of the Big Bang Theory

Singularity

• Universe originated from a single point, containing matter, energy, time, and space.

Big Bang and Inflation

• Single point rapidly expanded
• The universe rapidly cooled when it expanded, leading to the formation of quarks and gluons.
• Quarks and gluons are smaller than protons.
• Three quarks usually make up protons and neutrons.

Formation of Matter and Antimatter

• Matter includes protons/neutrons/electrons; antimatter includes antiprotons/antineutrons/positrons.
• The universe was dominated by matter over antimatter, with matter and antimatter having the same mass.
• Their charges and quantum numbers are different.

Annihilation

• Matter and antimatter particles collided and canceled each other out.
• Particles were destroyed and converted to energy in the form of photons in a fraction of seconds.
• Small excess of matter survived this annihilation that would be the universe
• Building blocks of the universe came from these remnants

Cooling Down of the Universe

• Universe cooled down, basic forces of nature/fundamental particles began to form.

Big Bang Nucleosynthesis

• Occurred within the first 3 minutes of big bang
• Protons and neutrons combined to form atomic nuclei (Hydrogen, Helium, and traces of Lithium).
• Most celestial bodies contain Hydrogen and Helium

Recombination

• Took place ~380,000 years after the Big Bang
• First neutral atoms were formed because electrons already existed
• Electrons + Nuclei = Neutral atoms
• Dense, opaque fog turned into Cosmic Microwave Background (CMB)

Dark Ages

• Lasted from 380,000 to 150 million years after the Big Bang.
• No light emitting bodies and was not transparent to light
• Filled with neutral hydrogen gas
• Gravity caused regions to clump together into dense regions.

Formation of Cosmic Bodies

• Lasted from 150 million to 1 billion years
• Marks the end of the dark ages, and the beginning of the universe
• First stars and galaxies formed

Nucleosynthesis and Primordial Elements

• Nucleosynthesis - "Nucleo" = Nucleus; "Synthesis" = Formation
• Nucleus is made of of protons and neutrons
• Nuclear fusion- A nucleus combines with another to form a larger nuclei
• Nuclear fission- A nucleus splits into smaller nuclei
• In the early universe, deuterium bottleneck was cleared thus nuclear reactions formed much higher elements

Cosmic Origin of Elements

• Big Bang Nucleosynthesis created Hydrogen, Helium, and small amounts of Lithium
• Stellar Nucleosynthesis created elements from Beryllium to Iron
• Supernova Nucleosynthesis created elements from Cobalt to Uranium
• Cosmic Ray Spallation- Lithium, Beryllium, and Boron are all lighter elements

Timeline of Atomic Theory

John Dalton

• In 1803, atomic theories proposed that atoms are solid spheres

J.J. Thomson

• In 1897, he proposed Electrons and the Plum Pudding Model/Raisin Bread Model
• Bread: Atom + Raisin: Electrons
• The electrons are embedded on the sphere, not inside the atom

Ernest Rutherford

• In 1911, he determined that protons are at the center of an atom
• A thin, gold foil was bombarded with alpha particles
• Concluded there is a positive charge inside the atom and placed it in the middle of the atom

Niels Bohr

• In 1913, electrons are arranged in shells/energy levels.
• Electrons are not embedded

James Chadwick

• In 1932, he discovered neutrons and the nucleus.

Erwin Schrödinger

• In 1926, he discovered electrons as waves
• Developed the quantum mechanical model of an atom

Atomic Identity

Atoms, Ions, Isotopes

• An ionis an atom or molecule that has electrical change
• Isotopes are particles of the same element with a different amount of neutrons.

Atomic Identity

• Isotopes are generally neutral.
• Atomic number (Z) = p = e
• Mass number (A) = p + n and n = A - p and p = A - n

Nuclear Reactions and Equations

• Nucleat reactions involve changing the structure of the nucleus and other atomic particles
• Nuclear Reaction = element / element + particle and Chemical Reaction = element + compound / compound.
• Alpha, beta, and gamma decay can be included.
• Locate the particle in the reaction before the arrow use: BOMBARDMENT and CAPTURE. After the arrow use: DECAY and RELEASE

Bombardment of Alpha Particle

• Target nucleus + alpha particle -> Product nucleus + Emitted particles.

Alpha Decay

• Unstable nucleus emits alpha particle
• Loss of an alpha particle

Electron Capture

• Drawing of an electron in an atom's nucleus

Beta-Minus Decay

• Loss of a beta or electron particle

Beta-Plus Decay

• Loss of a beta or electron particle

Gamma Radiation

• Emission of gamma ray
• Excited nucleus releases energy to return to stable state

Lesson 2: Chemical Bonding and Polarity of Molecules

Classification of Matter

• Matter classifies as Pure substances and Mixtures
• Pure substances classifies as Elements and Compounds
• Can be classified into Homogenous and Heterogenous

Elements

• Consist of simplest substances containing atoms
• Majority contains atoms, but some nonmetals are diatomic.
• Each element has unique properties and only has one identity

Compounds

• Chemical substances made up of 2 or more elements that are chemically bonded

Notable Scientists

Robert Boyle

• Founded elements and atomism and Boyle's law (Gas law).
• He believed matter was made up of atoms

Joseph Priestly

• Discovered O gas and phlogiston theory.

Joseph Proust

• Founded Law of Definite Proportion and important of Stoichiometry

John Dalton

• Founded Law of Multiple proportion

Antoine Lavoister

• Law of conservation of mass

Chemical Bonding

• Formation of a chemical bond between 2 or more atoms/molecules

Lewis Electron Dot Structure (LEDS)

• Created by Gilbert N. Lewis, used to show valence electrons using dots
• These valence electrons are freely moving and responsible for the formation of compounds
• There must be maximum of 8 electrons for an atom because Atoms have to follow the octet rule
• Molecules can be made stable.
• Noble gases are already stable and hydrogen only can have two valence electrons.

Ionic Bonds

• Metal and Nonmetal results to ionic compounds
• Metals lose electrons while nonmetals accept
• Metals become cations (+) and nonmetals become anions (-).
• There is a transfer of electrons.
• These are unequal number of protons and electrons

Naming Ionic Compounds

• Change suffix of nominal to ide retain the original name

Writing Chemical Formulas: Ternary Ionic Compounds

• Must use metal and polyatomic ion with criss cross method

Covalent Bonds

• The is one or more electrons sharing from one atom to another
• Uses nonmetal and nonmetal

Molecular Polarity

• Distribution of the molecules elections is the same and no atoms

Covalent Compounds

• Molecular compounds that contains one

Polar Covalent

• Electronegativity different in atoms

Nonpolar Covalent

• Electronegativity is exactly the same

Lesson 3: Intermolecular Forces of Attraction

Intramolecular Forces

• Electrons that share with molecule atoms

Intermolecular Forces

• Molecules that hold atom
• Dipole Dipole force: Attraction when there's opposite pole, hydrogen, and london dispersion forces
• Substances also influence with inter molecular forces
• Liquids cohesion with each other and water molecules
• Surfaces tensions with intermolecular forces

Lesson 5: Collision Theory and Chemical Reactions

• Surface area of solids and the amount of energy
• Collision theory - the principle that chemical reactions will only occur between particles when they collide with sufficient energy
• The factors affecting reaction rates are temperature, concentration, pressure, surface area, and catalyst