1604_L4_Basic chemistry_AY25-26_teacher version

Atoms can form Ionic and Covalent bonds to join together.

Covalent bonds can be classified as Polar and Nonpolar.

The four main types of organic molecules include Carbohydrates, Nucleic acids, Proteins, and Lipids.

Hydrogen bonds help molecules stick together, depending on the electronegativity of the atoms involved.

Protons, Neutrons, and Electrons are the three particles that make up an atom.

Atoms can form Ionic and Covalent bonds.

Water is a molecule that includes Hydrogen bonds, which cause molecules to stick together.

The four main types of organic molecules are Carbohydrates, Nucleic acids, Proteins, and Lipids.

Electronegativity depends on whether molecules are Polar or Nonpolar, affecting their interactions and properties.

• Proton: Positive charge, mass of approximately 1 amu, located in the nucleus.
• Neutron: No charge, mass of approximately 1 amu, located in the nucleus.
• Electron: Negative charge, mass of approximately 1/1836 amu, located in electron shells around the nucleus.

• Atomic Number: The number of protons in an atom's nucleus, which defines the element.
• Isotopes: Atoms of the same element with the same atomic number but different numbers of neutrons.
• Ions: Atoms that have gained or lost electrons, resulting in a net charge, but still retain the same atomic number.

• Polar Covalent Bonds: Unequal sharing of electrons due to differences in electronegativity, leading to partial charges.
• Non-Polar Covalent Bonds: Equal sharing of electrons, resulting in no charge separation.
• Molecular Properties: Polar molecules tend to be soluble in water (hydrophilic), while non-polar molecules are generally not soluble in water (hydrophobic).

The common elements in the human body include:

Polar molecules have a significant difference in electronegativity between the atoms, leading to a partial positive and negative charge, while non-polar molecules have an even distribution of charge due to similar electronegativities.

Protons, Neutrons, and Electrons are the three main particles that make up an atom.

An atom is the smallest unit of an element that retains its chemical properties. Its main components are:

1. Nucleus: Contains protons (positively charged) and neutrons (neutral).
2. Electrons: Negatively charged particles that orbit the nucleus in shells.

An element is a pure substance made of only one type of atom, defined by its atomic number, which is the number of protons. Elements have unique chemical and physical traits and are listed on the periodic table with their symbols (e.g., hydrogen (H), iron (Fe)).

The three smaller particles that make up an atom are:

1. Proton – a positively charged particle in the nucleus.
2. Neutron – a neutral particle with about the same mass as a proton, also in the nucleus.
3. Electron – a negatively charged particle found outside the nucleus, much smaller than protons and neutrons.

The electron has a negative charge and is located surrounding the nucleus of the atom.

A neutron has about the same mass as a proton. Both are located in the nucleus of the atom.

The proton has a positive charge and is located in the nucleus of the atom.

A neutron has no charge (neutral) and has a mass of 1 (relative to protons).

An element is defined as a pure substance consisting of atoms that have the same number of protons, which is also known as the atomic number.

The atomic number of hydrogen is 1, which signifies that it has 1 proton in its nucleus.

Oxygen has 8 protons, and its atomic number is therefore 8.

The number of protons in an atom serves as the element ID card, as it is the only feature that uniquely defines an element.

Changing the proton count alters the element itself; for example, adding 1 proton to carbon (6 protons) transforms it into nitrogen (7 protons).

• Ions: Formed by losing or gaining electrons while the proton count remains the same.
• Isotopes: Variants of an element that differ in the number of neutrons, while the proton count defines the element.

The proton count defines the element, while isotopes vary in the number of neutrons.

Helicobacter pylori produces urease, which breaks down urea into carbon dioxide (CO2) and ammonia (NH3).

1. The patient swallows a capsule or fluid containing labeled urea (C13 or C14).

2. If H. pylori is present, its urease enzyme splits the labeled urea into labeled CO2 and ammonia.

3. After 10–30 minutes, the patient exhales into a collection bag.

4. The breath sample is analyzed for labeled CO2; higher levels indicate an infection.

A higher level of labeled CO2 in the breath sample indicates the presence of Helicobacter pylori infection, as it shows that urease has broken down the labeled urea.

The C13/C14 urea breath test tracks enzymatic cleavage of urea into CO2.

The bulk elements that constitute 99% of the human body's mass are:

1. Oxygen (O)
2. Carbon (C)
3. Hydrogen (H)
4. Nitrogen (N)
5. Calcium (Ca)
6. Phosphorus (P)

The electron shell pattern for the first four shells is 2, 8, 8, 2. This pattern applies to the first 20 elements of the periodic table.

Trace elements, such as Iron (Fe), Zinc (Zn), Copper (Cu), and Iodine (I), are critical for various biological functions despite being present in tiny amounts. They play essential roles in processes like enzyme function, hormone production, and overall metabolic health.

The major elements are:

1. Oxygen (65.0%)
2. Carbon (18.5%)
3. Hydrogen (9.5%)
4. Nitrogen (3.0%)
5. Calcium (1.5%)
6. Phosphorus (1.0%)

The minor elements are:

1. Sulfur (0.25%)
2. Potassium (0.20%)
3. Sodium (0.15%)
4. Chlorine (0.15%)
5. Magnesium (0.05%)
6. Iron (0.006%)

They act as cofactors for enzymes and proteins, facilitating various biochemical reactions essential for life.

They act as cofactors for enzymes, facilitating various biochemical reactions essential for life.

Cellular respiration, water, and organic molecules.

Carbon.

Proteins and nucleic acids (DNA/RNA).

Bone structure, muscle contraction, and signaling.

ATP production, DNA/RNA structure, and bone mineralization.

Nerve impulses and electrolyte balance.

It contributes to protein structure through disulfide bonds and acts as an enzyme component.

Nerve function and fluid balance.

It acts as an enzyme cofactor and is important for muscle and nerve function.

Oxygen transport in hemoglobin and as a component of enzymes.

It serves as an enzyme cofactor and is important for immune function.

An atom consists of protons, neutrons, and electrons.

The concept map mentions ionic and covalent bonds.

The four main types of organic molecules are:

1. Carbohydrates
2. Nucleic acids
3. Proteins
4. Lipids

Molecules stick together because of hydrogen bonds.

Whether a molecule is polar or nonpolar depends on electronegativity.

The minimum number of atoms required to form a molecule is two.

A molecule is defined as two atoms that are bound together via a chemical bond.

The Octet Rule states that atoms gain, lose, or share electrons to achieve 8 valence electrons, similar to noble gases. An exception is for Hydrogen (H) and Helium (He), which only require 2 electrons (known as the duet rule).

Atoms are most stable when their outer shells are full because this configuration minimizes energy and maximizes stability. Bonding with other atoms helps to fill the vacancies in their outer shells.

In ionic bonds, electrons are transferred from one atom to another, while in covalent bonds, electrons are shared between atoms.

Ionic bonds are formed between a metal and a non-metal, whereas covalent bonds are formed between non-metals.

Ionic bonds are usually found in a solid state, while covalent bonds can exist in any state (solid, liquid, or gas).

Ionic bonds generally have a high melting point, while covalent bonds typically have a low melting point.

An ionic bond is formed when one atom donates one or more electrons to another atom. For example, a sodium atom (Na) donates its single valence electron to a chlorine atom (Cl), resulting in the formation of Na+ and Cl- ions, which then combine to form sodium chloride (NaCl).

The transfer of electrons in ionic bonding leads to the formation of ions with full valence shells. This process stabilizes the atoms involved, as seen in the formation of sodium chloride (NaCl) from Na+ and Cl- ions, which arrange in a repeating pattern to create salt crystals.

When sodium (Na) donates an electron to chlorine (Cl), it forms a positively charged sodium ion (Na+) and a negatively charged chloride ion (Cl-). These ions combine to form the compound sodium chloride (NaCl).

A covalent bond is formed when atoms share electrons. In a methane molecule (CH4), one carbon atom shares its four outer shell electrons with four hydrogen atoms, allowing all five atoms to fill their outer energy shells.

Atoms consist of protons, neutrons, and electrons.

Atoms can join by ionic or covalent bonds to form molecules.

Water causes organic molecules to stick together because of hydrogen bonds.

The four main types of organic molecules are carbohydrates, nucleic acids, proteins, and lipids.

Covalent bonds may be polar or nonpolar depending on electronegativity.

Electronegativity increases from left to right across a period and increases from the bottom to the top of the periodic table.

Nonmetals generally have high electronegativity, with fluorine being the highest.

Metals generally have low electronegativity.

The difference in electronegativity of the bonding atoms can be used to predict the polarity of the bond.

In the H₂ molecule, electrons are shared equally, resulting in a nonpolar bond.

In the HCl molecule, electrons are shared unequally, leading to a polar bond.

Polar molecules have unequal electron sharing (e.g., O-H, N-H bonds), while non-polar molecules have equal electron sharing (e.g., C-H, C-C bonds).

Polar molecules are hydrophilic and water-soluble, whereas non-polar molecules are hydrophobic and fat-soluble.

Polar Molecules:

• Water (H₂O): Found in blood plasma and cytoplasm.
• Glucose (C6H12O6): Used for cellular energy.
• Amino Acids (e.g., serine): Building blocks of proteins.

Non-Polar Molecules:

• Oxygen (O₂): Involved in gas exchange in lungs.
• Cholesterol: Component of cell membranes.
• Fatty Acids: Used for energy storage in fats.

Ionic bond

Non-polar covalent bond

Polar covalent bond

Ionic bond

Amphipathic molecule (e.g., phospholipids)

Ionic bond

Non-polar covalent bond

Polar covalent bond

Ionic bond

Amphipathic molecule

Functional groups are specific groups of atoms within molecules that determine their chemical reactivity and biological function. They play a crucial role in defining the properties and behaviors of organic compounds.