Kinetic Theory, Atomic Structure, and Bioelements Explained
Kinetic Theory of Gases
The kinetic theory of gases states that gases are formed of very small particles separated from each other, moving constantly. Gases occupy the entire volume of the container. Gas pressure is exerted on the walls of the container due to the constant collisions of the gas particles with the walls.
The more rapidly the particles move, the higher the temperature. Solids do not expand or compress easily, maintaining a constant volume and shape. Their particles are strongly united in a rigid structure, making them difficult to compress or expand. Solids have a higher density because their particles are very close together.
Liquids
Liquids dilate slightly and are difficult to compress, maintaining a constant volume. The particles have a variable shape with weak unions, allowing them to flow. The structure is not as rigid as solids, adapting to the container. Liquids are difficult to compress.
Gases
Gases have a lower density than solids and liquids because the particles are more separated. Gases expand to occupy the entire volume available and are easily compressed because their molecules are very separated.
Atomic Structure
Thomson’s Model
Thomson proposed that atoms contain one or more negatively charged particles called electrons. The atom was thought to be a mass with positive charge, with electrons embedded within it, so that the negative charge of the electrons compensated for the positive charge, making the atom neutral.
Rutherford’s Model
Rutherford’s experiments showed that most particles passed through a gold foil without deflection. A small proportion of particles were deflected slightly, and about 1 in 10,000 rebounded. This suggested that the atom consists of a very small, dense nucleus containing most of the mass and positive charge, surrounded by electrons orbiting the nucleus.
Key Atomic Numbers
- Atomic Number (Z): Number of protons
- Mass Number (A): Number of protons + Number of neutrons
Isotopes
Isotopes are elements that have the same atomic number (Z) but different mass numbers (A).
Bioelements
Bioelements are the elements that make up living beings. Approximately 99% of living matter consists of C, H, O, N, Ca, P, Mg, K, Na, Cl, and S. About 0.1% consists of trace elements.
Oligoelements
Oligoelements are indispensable for living organisms, such as Fe, Mn, Cu, Zn, and Co.
Functions of Specific Bioelements
- Ca: Bone and teeth development, blood coagulation, and vitamin D production. Deficiency can cause rickets.
- P: Forms part of cell membranes and nucleic acids.
- Mg: Activated in processes that create energy in living beings, regulates muscle function and nerve impulses. Deficiency causes general weakness.
- Fe: Involved in growth and the production of hemoglobin. Deficiency causes anemia and reduces resistance to infection.
- Zn: Facilitates cell development, scar formation, and wound healing. Deficiency can cause dwarfism.
- Mn: Activates processes that produce energy in living beings and helps form bones. Deficiency affects memory.
Molecules and Crystals
Molecules
Molecules are groups of atoms that can belong to the same or different elements. A molecule is the smallest part of a substance that retains its chemical properties. A substance is a set of molecules.
Crystals
Crystals are a form of matter whose atoms form an ordered structure that extends in three dimensions.
Chemical Reactions
Collision Theory
Chemical reactions occur when molecules of reactants collide with enough energy to break bonds and reorganize, forming new molecules.
Exothermic Reactions
Exothermic reactions produce energy.
Acids and Bases
Acids
Acids have a sour taste, release hydrogen ions (H+) when dissolved in water, dissolve some metals, and dissolve marble, releasing CO2. Their properties disappear when reacted with a base.
Bases
Bases have a bitter taste and a slippery touch, favor fat dissolution, and their properties disappear when reacted with an acid.