QUARTER 2 SCIENCE 9.pptx hhfcdlif97v/ vgjyt

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1. Electronic structure of matter

2. Atomic theories: John Dalton (Solid Sphere Model) All matter is made up of tiny, indivisible particles called atoms. All atoms of a specific element are identical in mass, size, and other properties. However, atoms of different element exhibit different properties and vary in mass and size. Atoms can neither be created nor destroyed.

3. Atomic theories: Joseph John Thomson (Plum Pudding Model The atom was spherical in shape consisted of the negatively charged particles that float in a positively charged soup. The positive and negative charge in the atoms were equal and uniformly distributed.

4. Atomic theories: Ernest Rutherford (Nuclear Model) The positively charge d particles and most of the mass of an atom was concentrated in an extremely small volume and called this region of the atom as nucleus. Rutherford model proposed that the negatively charged electrons surround the nucleus of an atom.

5. Atomic theories: Niels Bohr (Planetary Model) Electrons revolve around the nucleus in stable orbits without emission of radiant energy. Each orbit has a definite energy and is called an energy shell or energy level. It emits or absorbs energy when it jumps from one orbit to another. When it jumps from a higher energy level to lower energy level it emits energy while it absorbs energy when it jumps from a lower enrgy to hgher energy level.

6. Atomic theories: Erwin Schrodinger (Electron Cloud Model) Schrodinger’s atomic model originally conceived of electrons as matter waves. The spectral emission lines of both neutral and ionized atoms. The modification of energy levels when there is a magnetic or electric field.

7. Electrons configuration - The arrangement of electrons in an energy level around a nucleus.

8. Sub-levels maximum number of electrons S – (sharp) 2 P – (principal) 6 D – (diffuse) 10 F – (fundamental) 14

9. Steps in writing electron configuration 1. Determine the atomic number of the element.

10. Steps in writing electron configuration 2. Use the electron configuration mnemonic device.

11. 3. Follow the three principles in writing the electron configuration. a. AUFBAU PRINCIPLE – requires that the electrons occupy the lowest possible energy level before filling up the next.

12. b. Pauli’s Exclusion Principle - State that no two electrons can have the same set of four quantum number; the spin quantum number limits the number of electrons in an orbital to a maximum of two.

13. c. Hund’s Rule – requires that the electrons fill the orbitals in a sub level, one by one, before pairing the electrons in an orbitals spin in opposite direction.

14. Write the electron configuration for the element flourine

15. Quantum Numbers – determines the location and arrangement of electrons in an atom. Orbitals – probability where electrons can be found

16. PRINCIPAL QUANTUM NUMBER – (n) refers to the energy level of an electron.

17. ANGULAR MOMENTUM (I) –refers to the shape of the orbitals = n – 1 Example: = 3 (I) = 3-1 (I) = 2 I =0, 1, 2

18. Angular Momentum

19. Magnetic Quantum Number – (m)

20. SPIN QUANTUM NUMBER – (m) Describe the rotations or the spins on how the electrons move on their own axis as they move around the nucleus. The spinning charge create the magnetic field. The electron spinning clockwise has the – ½ values. The electrons that are spinning counter – clockwise have the + ½ values.