Kinetic Particle Theory PDF

# Kinetic Particle Theory Matter is made up of particles that are constantly in motion. This energy that causes motion is called kinetic energy. The amount of kinetic energy is related to its temperature. Phase change happens when the temperature changes. There are attractive forces present bet...

# Kinetic Particle Theory Matter is made up of particles that are constantly in motion. This energy that causes motion is called kinetic energy. The amount of kinetic energy is related to its temperature. Phase change happens when the temperature changes. There are attractive forces present between molecules. There is space present between particles. ## Diagram: States of Matter - Solid: Particles are tightly packed. - Liquid: Particles are less tightly packed and move freely. - Gas: Particles are far apart and move randomly. ## Interconversion of States of Matter - **Solidification:** Conversion of liquid into a solid. - **Melting:** Conversion of a solid into a liquid. - **Freezing:** Conversion of a liquid into a solid. - **Evaporation:** Conversion of a liquid into a gas. - **Condensation:** Conversion of a gas into a liquid. - **Sublimation:** Conversion of a solid into a gas. ## Melting & Boiling - **Melting:** Particles gain kinetic energy, turning into a liquid. - **Boiling:** Substance changes from liquid to gas at a specific temperature. ## Evaporation - Evaporation also turns the liquid into a gas, but differs from boiling in how they happen. - Boiling occurs when the liquid reaches a specific boiling point. - Evaporation happens at different temperatures and is a slower process. ## Heating Curve - A-B: Melting of solid. - B-C: Temperature increases, but state is a mix of solid and liquid. - C-D: Liquid. - D-E: Boiling of liquid. - E-F: Gas. ## Cooling Curve - F-E: Gas. - E-D: Temperature decreases, but state is a mix of liquid and gas. - D-C: Liquid. - C-B: Water freezing. - B-A: Ice solid. ## States of Matter: Questions **Q: Use the ideas of kinetic theory to explain the differences between boiling and evaporation.** **A:** According to kinetic theory, molecules start colliding when the temperature increases. * **Boiling:** Temperature increases rapidly, resulting in molecules colliding with each other faster and turning into gas. * **Evaporation:** However, molecules do not collide with each other. They only get enough heat to move from the surface - that is all the molecules also change their state slowly. That's why evaporation is a slower process than boiling. Evaporation can occur at any temperature, but boiling requires a specific temperature to occur. **Q: Using the kinetic theory, explain why the rate of diffusion increases when the temperature increases.** **A:** When the temperature of a gas increases, the kinetic energy of its particles also increases. This means that the particles are moving faster and they more faster, they collide with each other more frequently which helps to disperse the particles more quickly leading to faster the rate of diffusion. ## Heating and Cooling Curves - A **heating curve** is a graph that shows how the state of a substance changes as heat is applied. - A **cooling curve** is the opposite of a heating curve. It shows how the state of a substance changes as it loses heat. ## The Structure of an Atom - The smallest part of an element which participates in a chemical reaction is called an **atom**. - **Protons:** Positively charged particles, located in the nucleus. - **Electrons:** Negatively charged particles, located in shells. - **Neutrons:** Neutral particles located in the nucleus. ## Subatomic Particles: Terms - **Proton number:** # of protons present in the nucleus of an atom. - # of protons is equal to the number of electrons in an atom. - Denoted by "Z". - Noted below the symbol of an element. - **Nucleon number:** Total # of protons and neutrons in an atom. - Also known as "atomic mass". - Denoted by "A". - Noted on the top of the symbol of an element. ## Calculating the Number of Electrons, Protons and Neutrons Given the following, calculate the number of protons, electrons, and neutrons in the atoms. 1. **Cu:** atomic number = 29, neutron number = 35 - # Protons = 29 - # Electrons = 29 - # Neutrons = 35 2. **Fe:** atomic number = 26, neutron number = 30 - # Protons = 26 - # Electrons = 26 - # Neutrons = 30 3. **Ag:** atomic number = 47, neutron number = 61 - # Protons = 47 - # Electrons = 47 - # Neutrons = 61 4. **Pb:** atomic number = 82, neutron number = 125 - # Protons = 82 - # Electrons = 82 - # Neutrons = 125 ## Isotopes - Atoms of the same element having the same atomic number (proton number) but different atomic mass (neutron number). - **Example:** - **H:** 1 proton and 0 neutrons - **2H:** 1 proton and 1 neutron - **3H:** 1 proton and 2 neutrons ## Electronic Configuration - The structure of an atom can be represented in two ways: - **Using diagrams:** Electron shell diagram. - **Electronic configuration:** Written notation. - **Electron orbits around the nucleus in shells (or energy levels).** - The further away from the nucleus the electron is in an orbit, the more energy it has. - E.g., the first shell (K) = 2e. - **The outermost shell of an atom is called the valence shell.** ## Ions - Ions are formed when an atom loses or gains electrons to become stable. - **Positively charged ions:** Atoms lose electrons. - **Negatively charged ions:** Atoms gain electrons. ## Electronic Configuration and Periodicity - There is a clear relationship between the electronic configuration and the periodic table. - The number of electrons in the occupied shells of an atom shows the period in which the element is in. - The last notation shows the number of outer electrons the atom has - showing the group that element is in. - Elements in the same group will have the same number of outer shell electrons. ## Noble Gases - The atoms of the group VIII elements (noble gases) all have a full outer shell of electrons. - They are unreactive as they have a full outer shell and are very stable. ## Electronic Configuration of Ions: Examples 1. **Mg:** 2, 8, 2 (loses 2 electrons to become a positively charged ion) - Mg+2: 2, 8 2. **Cl:** 2, 8, 7 (gains 1 electron to become a negatively charged ion) - Cl: 2, 8, 8 3. **Na:** 2, 8, 1 (loses 1 electron to become a positively charged ion) - Na+: 2, 8 ## Isotopes Continued - # of neutrons = atomic mass - # of protons - **Example:** - Atomic mass of C-14 = 14 - # of neutrons = 14 - 6 = 8 ## Properties of Isotopes - Isotopes of the same element display the same chemical characteristics. This is because they have the same number of electrons in their outer shells and therefore the same electronic configuration. - The difference between isotopes is that # of neutrons which are neutral particles within the nucleus and add only to the mass of an atom. ## Isotopes and Physical Properties - The difference in mass affects the physical properties, such as density, boiling point, and melting point. - Isotopes are identical in appearance. - **Example:** A sample of C-14 would look no different from C-12. ## Electronic Configuration and Reactivity - The electronic configuration of an atom can determine its reactivity. - Atoms with nearly full valence shells are highly reactive since they compete to gain electrons to complete their shell. - Atoms with nearly empty valence shells are also highly reactive because they compete to lose electrons easily to achieve a stable configuration. ## Significance of Nobel Gas Configuration - The noble gas configuration is significant because it is a highly stable arrangement. They have full valence shells, making them chemically unreactive. ## Structure, Bonding and Properties: The Formation of Ions - An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons. - An atom will lose or gain electrons to become more stable. - The loss or gain of electrons takes place to gain a full outer shell of electrons, which is a more stable arrangement of electrons, would be the same as that of a noble gas. ## Ionization of Metals and Non-Metals - **Metals:** All metals can lose electrons to other atoms to become positively charged ions known as cations. - **Non-metals:** All non-metals can gain electrons from other atoms to become negatively charged ions known as anions. ## Why do Atoms Bond Together? - Some atoms are reluctant to combine with other atoms and exist in the air around us as single atoms. These are the noble gases and have a very stable electron arrangement. - **Example:** He (2, 8, 8), Ne (2, 8) and Ar (2, 8, 8). - All other atoms, therefore, bond together to become electronically more stable. - The new electronic arrangement (bonding) produces new substances of bond. - The chemical bonding usually involves only the outer shells and valency electrons. - The chemical bond refers to the strong electrical force of attraction between the atoms or ions in the structure. ## Combining Power and Valency - The combining power of an atom is sometimes referred to as its valency. - Its value is linked to the number of the outer electron of the original atom.