Nucleosynthesis: Elements Formation

• Elements is the study of the formation
• Nuclear reactions, fusion, fission, isotopes, atoms, and protons are key terms.
• Neutrons, electrons, nucleosynthesis, Big Bang, stellar, and supernova are key terms

Nucleosynthesis

• Nucleosynthesis refers to the creation of new atomic nuclei.
• These nuclei are at the center of atoms and are made up of protons and neutrons.

Nuclear Reactions

• Fusion is when two or more things join together to form a single entity
• Fission is splitting something into two or more parts

Atomic Number

• Atomic number indicates the number of protons found in the nucleus.

Mass Number

• Mass number represents the total number of protons and neutrons in the nucleus.

• The element symbol is represented as X.

• The mass number (no. of protons + neutrons) is represented as A, and is located on the top left of the element symbol.

• The atomic number (no. of protons) is represented as Z, and is located on the bottom left of the element symbol.

• Hydrogen's atomic number is 1, its atomic weight is 1.00784:1.00811, and its electronic configuration is 1s.

Big Bang Theory

• The Big Bang Theory is an accepted scientific theory for the origin of the universe based upon multiple lines of evidence.
• It is one of the most popular attempts to describe the early universe.
• It was first proposed Belgian astrophysicist and priest Abbe Georges Lemaitre (1894-1966).
• The name "Big Bang" was coined by British astronomer Fred Hoyle in 1949.
• All matter and energy were compressed at a single point at the time of the expansion.

Abundance of Elements

• The expanding universe consists of light and heavy elements.
• It also consists of heavier elements than iron.

Major Types of Nucleosynthesis

• Primordial Nucleosynthesis is also known as Big Bang Nucleosynthesis.
• Stellar Nucleosynthesis is a type of Nucleosynthesis.
• Supernova Nucleosynthesis is a type of Nucleosynthesis.

Primordial Nucleosynthesis

• Protons, neutrons, and electrons were moving around without control.
• Rapid cooling occurs during the first three minutes of the universe's rapid expansion.
• Rapid cooling slows down sub-atomic particles and provides more opportunities for light elements to bind together.
• The lightest elements include hydrogen (1H), helium (2He), lithium (3Li) and beryllium (4Be).

Neutrons and Protons

• Mass number is protons + neutrons.
• Number of neutrons is the mass number – atomic number.
• Atomic number = number of protons = number of electrons.

Isotopes

• Isotopes are atoms of the same element having the same number of protons and electrons but a different number of neutrons.
• Deuterium (Hydrogen-2) and Tritium (Hydrogen-3) are isotopes of hydrogen.

Deuterium

• Deuterium (D) is an isotope of hydrogen and is formed from the fusion of a proton and a neutron.
• It's accompanied by the emission of high-energy photon (y) and is a stable element.
• p + n → ²H + y is the equation.

Tritium

• Tritium (T) or hydrogen-3 was produced from the fusion of two deuterium nuclei and a release of a proton.

• ²H + ²H → ³H + p is the equation.

• It is an unstable element.

• Isotopes of Lithium include Lithium-6, Lithium-7, and Lithium-8.

• Lithium-6 and Lithium-8 are unstable.

• Lithium 7 is stable.

• Unstable isotopes undergo radioactive decay.

Stellar Nucleosynthesis

• It is the process by which elements are created within the stars by combining the protons and neutrons together from light elements.
• Stars, which are giant balls mostly made of Hydrogen and Helium, act as sites for nuclear reactions in the universe.
• Stars fuse light elements to form heavier elements.
• Heavy elements: Boron, Carbon, Nitrogen up to Iron.

Supernova Nucleosynthesis

• It is the process by which heavier elements than Iron (Fe) are created.
• This is facilitated by two characteristics, including extreme temperatures, and abundant neutrons.
• Supernova stars reach extreme heat: 100 Billion °C, which is 6000x hotter than the core of sun.

Periodic Table

• Mass number is protons + neutrons
• Neutrons are mass number – atomic number
• Atomic number = protons = electrons
• In 1913, Henry Mosely discovered the atomic number is the most fundamental property of an element, therefore it’s included the Modern periodic table of elements.
• The periodic table was created by Dmitri Mendeleev, who arranged elements by increasing atomic masses and grouped them by properties.

Electronegativity

• Electronegativity is the ability of an atom to attract shared electrons in a chemical bond.
• It measures how strongly an atom attracts electrons when bonding with another atom.
• Electrons are negatively charged subatomic particles.
• A chemical bond is the force that holds atoms together.

Electronegativity Trends

• Electronegativity increases across a period (left to right).
• Electronegativity decreases down a group (top to bottom).

General Pattens

• Atoms have more protons in the nucleus as moving across a period, which increase the positive charge, pulling electrons closer.
• Fluorine (F) has higher electronegativity than Lithium (Li).
• As moving down a group, atoms have more energy levels (shells).
• The outermost electrons are farther from the nucleus, reducing the pull of attraction.
• Chlorine (Cl) has higher electronegativity than Iodine (I).
• A group is a column on the periodic table with elements with the same number of valence electrons.
• A period is a row on the periodic table where elements have the same number of electron shells.
• There are 7 periods and 18 groups.

Exceptions to Electronegativity Trend

• In Group II-B, (Zinc, Cadmium, Mercury), the trend is reversed and, electronegativity increases from top to bottom.
• In Group III-A, Aluminum (Al) has higher electronegativity than Gallium.
• Most noble gases, like Helium, Neon, and Argon, do not form bonds easily.Their electronegativity values are not usually measured.
• Krypton (Kr) and Xenon (Xe) which are noble gas do form compounds, and have measurable electronegativities.
• Francium (Fr) has the weakest ability to attract electrons, with an electronegativity value of about 0.7.
• Electronegativity helps predict bond types, reactivity, and molecular behavior.
• A trend is a predictable pattern in the periodic table.
• Exceptions are the circumstances where a trend does not adhere to the general rule

Polarity

• Polarity is about how atoms share electrons in a molecule.
• Molecules either share them equally, or one atom pulls electrons closer to itself, creating a slight charge difference.
• Polarity depends on the electronegativity of the atoms involved in the bond.
• Polarity affects how a molecule interacts with other substances, dissolving in liquids, boiling and melting points, and biological functions.

Bonds

• A Bond is the connection between atoms in a molecule.
• A Covalent Bond is formed when atoms share electrons
• An Ionic Bond is formed when one atom transfers electrons to another, creating charged particles (ions).

Octet Rule

• The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell.
• When atoms have fewer than eight electrons, they tend to react and form more stable compounds.
• A compound is a substance formed when two or more elements are chemically bonded together, like water (H2O).

How to Determine Polarity

• Step 1: Look at the atoms involved in the bond while comparing electronegativity values.

• Step 2: Observe and consider the bond.

• A Nonpolar Bond shares electrons equally between atoms.

• O2 (oxygen gas) is an example of nonpolar bond.

• A Polar Bond electrons are shared unequally because one atom pulls them more strongly. H2O (water) is an example of polar bond.

• In an ionic bond, a metal and nonmetal bond, while a covalent bond forms between two nonmetals.

• Metalloids also form covalent bonds with non metals.

• Covalent bonds may be polar or non-polar.

Organic Molecules

• Oxygen-hydrogen exhibits an electronegativity difference is 1.4, such as in a water molecule.
• Carbon tetrachloride, CCl4, exhibits an electronegativity difference is 0.5.
• Unequal sharing exhibits between 0.5-1.7 (moderate) electronegativity differences.

Non Polar Covalent Bonds

• Examples of this bond type include hydrogen, chlorine, bromine, iodine, oxygen and nitrogen.
• Equal sharing exhibits between 0.0 and 0.4 (smaller) electronegativity differences.

Ionic bonds

• Examples of ionic bonds include Lithium Fluoride, Lithium Chloride, Lithium Bromide, and Lithium Iodide.
• Barium Selenide, Barium Sulfide, and Copper (I) Fluoride are also ionic bonds.
• There is no sharing of charge in ionic bonds; electron transfer occurs, and the electronegativity difference is large, at over 1.7.

Biomolecules

• Biomolecules are molecules of life.

• A learning objective is to explain how the structures of biological macromolecules determine their properties and function.

• There are (4) types of macromolecules including CARBOHYDRATES, LIPIDS, PROTEINS, and NUCLEIC ACIDS.

• Macromolecules are large molecules where each has subunit called a monomer.

• A monomer is one basic unit or subunit

• When monomers bond together through polymerization, the resulting structure is a polymer

• Macromolecule is the same as of of polymer.

Organic molecules

• Carbohydrates consist of a monosaccharide and polysaccharide.
• Proteins consist of an amino acid and polypeptide.
• Lipids consist of a fatty acid and glycerol, and its polymer is a lipid.
• Nucleic acid's monomer and polymer are both nucleotide and nucleic acid, respectively.

Characteristics and Function of Organic Molecules

• Carbohydrates (C-H-0) exist as monosaccharides, disaccharides, and polysaccharides.
• Carbohydrate monomers include glucose, which acts an immediate source of energy and stored energy.
• Proteins (C-H-O-N) exist structurally, enzymatically, carrer, hormonoly, and contractile.
• Its monomeric building blocks are amino acids giving support, metabolism, transport regulation, and motion.
• Nucleic acid (C-HO-N-P) exists as DNA and RNA, with functions pertaining to the storage of genetic information, a function of protein synthesis.
• Lidids (C-H-O) are fats, phospolipids, etc. which yield fatty acids, and they aid in long term energy storage

Proteins

• Proteins are the most abundant organic compound found in living things.
• They have fundamental structural and functional frameworks in cells.
• Its' polymer is proteins, and its monomer is amino acids.
• Its construction is facilitated by Carbon, Hydrogen, Oxygen, and Nitrogen (CHON).

Functions of Proteins

• Proteins control mechanical support, generating movement, immune protection, transmitting nerve impulses, controlling growth and differentiation.
• They build and repair muscles and tissues and act as enzymes.
• There are several protein types, and their functions include:
  • Enzymatic proteins: Serves as catalysts to speed up chemical reactions (Amylase, Urease etc.)
  • Structural proteins: Support (Keratin)
  • Storage of Protein: Storage of amino acids(Albumin).
  • Support of Transport proteins: Transport of other substances (Hemoglobin).
  • Support for Contractile and motor protein: Movement (Actin and Myosin).
  • Support of Defensive proteinss: Protection againist deseases (antibodies).
  • Support of Hormonal proteinss: Coodination of organic activities (Insulin, Growth Hormones).
• There are 20 primary amino acids.

Carbohydrates

• Carbohydrates is the chief energy source of all organisms, serving as a backbone to other molecules.
• They combine with protein to form the structural component for living cells.
• Carbohydrates are "sugars" and are also called hydrates of carbon or saccharides.
• The 3 main groups are Monosaccharides, Disaccharides, and Polysaccharides.
• Its building block is Saccharine or Glucose with elements (C, H, O).

Nucleic acids

• Nucleic acids are macromolecules built as a long chain of monomers called nucleotides.

• The primary function is the storage and transmission of genetic information.

• Two types, RNA and DNA.

• DNA (Deoxyribonucleic acid):Contains genetic material which is the hereditary information of living organisms.

• It contains the organization of enzymes, thus determining the chemical activities of the cell.

• ADN contains the following Nitrogenous bases: Adenine is linked to Thymine (A –T); and Guanine is linked to Cytosine (G-C).

• RNA (Ribonucleic acid):Shares a similar structure as DNA, but is singular and stranded.

• Carries out the most genetic material forviruses.

• Has similar Nitrogenous bases: Guanine linked to Cytosine (G-C) and Adenine linked to Uracil (AU).

Lipids

• Lipids serve as the highest source of energy for the body.
• These are stored fats derived from carbohydrates, which can be oxidized to release energy.
• Lipids are fats, and a gram of fat contains over twice the energy content of a gram of carbohydrates.
• The monomers are Fatty acids and Glycerol.

Classification of Lipds

• Fats are also known as triglycerides or blood fats, circulating throughout the bloodstream along with cholesterol.
• ex. Cholesterol one of the most important steroids and a component of animal cell membrane and a precursor for the synthesis of a number of steroid.
  • Such steroid hormone examples include testosterone, progesterone, and estrogen
  • the liver produces cholesterol.

Phospholipids and Waxes

• Phospholipids exist in cell membranes, which are semipermeable or selectively permeable to certain substances.
• Waxes make up the cuticle covering the surface of leaves and stems of plants, while protecting the skin/fur of some animals.