Grade 9 Science - Electron Configuration PDF

GRADE 9 SCIENCE TOPIC 2.5 ELECTRON CONFIGURATION  LESSON OBJECTIVES At the end of the session, you are expected to: 1. Define orbital; 2. Describe electron configuration; and 3. Write the correct electron configuration of given elements using the long hand...

GRADE 9 SCIENCE TOPIC 2.5 ELECTRON CONFIGURATION  LESSON OBJECTIVES At the end of the session, you are expected to: 1. Define orbital; 2. Describe electron configuration; and 3. Write the correct electron configuration of given elements using the long hand and abbreviated method following the Aufbau principle QUANTUM MECHANICAL MODEL In Schrodinger’s model, electrons do not follow sharply defined orbits, but rather are found in orbitals. QUANTUM MECHANICAL MODEL Different Perspectives of s orbitals Orbitals are regions in which an electron can be found, and the probability of finding an electron is described by mathematical equations proposed by Schrodinger. Orbitals of various energies are separated by nodes where electrons are forbidden. This Photo by Unknown Author is licensed under CC BY-SA-NC Electrons belong to orbitals of specific energies.  ORBITAL 🔴 An orbital is a region of space where there is a probability of finding the electrons.  ELECTRON CONFIGURATION 🔴The electron configuration shows the specific arrangement of electrons in the orbitals of an atom. 🔴An orbital is a region of space where there is a probability of finding the electrons. sharp principal diffuse fundamental  ELECTRON CONFIGURATION 🔴Electron configuration is described with a notation energy number of electrons or symbol that contains three important level in the subshell 1s 2 information. 1. First, the number of energy level or the shell (i.e., 1, 2, 3...). 2. Second, the letter that describes the orbital type or the subshell/sublevel which can either subshell be s, p, d, or f (shape of the orbital). Number of Subshell Electrons 3. Third, the superscript shows the number of s ≤2 electrons in a specific subshell. (Each subshell can only occupy a specific maximum p ≤6 number of electrons.) d ≤ 10 f ≤ 14 ELECTRON CONFIGURATION Total No. of Max. No. of Energy electrons Subshell Electrons in Level per energy each subshell level 1 1s 2 2 2 2s 2 8 2p 6 3 3s 2 3p 6 18 3d 10 4 4s 2 4p 6 4d 10 32 4f 14  AUFBAU PRINCIPLE 🔴Aufbau principle is used to reproduce the electron configurations of the ground states of atoms by successively filling the sublevels with electrons in specific order. 🔴In other words, the electrons in an atom are filled in increasing order of energies. 🔴 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6… EXAMPLE 🔴 Sodium (Na) = 11 e- 1. Its first two electrons 1s2 2s2 2p6 3s1 would fit in the lowest energy possible, 1s (1s2); 2. The next two electrons would occupy 2s (2s2); 3. The next six electrons will go to 2p (2p6); and 4. One more electron to 3s (3s1), accounting for a total of 11 electrons.  METHOD 1: LONG HAND CONFIGURATION 1. Look for the atomic number of the given element. 2. Follow the notation starting with the lowest energy level until such time that the number of electrons of the element are distributed. 3. Check if the correct notation was followed and add the total number of electrons indicated by the superscripts. METHOD 1: LONG HAND CONFIGURATION N Cl Ti K Ne  MORE EXAMPLES 🔴Which of the following electron configurations are possible? Explain why others are not possible. 1. 1s2 2s2 2p1 = 2. 1s2 2s2 2p6 3s2 3p6 4s2 3d2 = 3. 1s2 2s2 2p6 3s2 = 4. 1s1 2s3 2p6 3s2 = 5. 1s2 2s1 2p6 3s2 3p1 = 🔴Write the electron configuration of the following ions. 1. Mg2+ = 2. O2– = 3. N3– = 4. Al3+ = 5. K+ =  METHOD 2: NOBLE GAS/ABBREVIATED CONFIGURATION Cu F 1. Use the last noble gas that is Sr located in the periodic table right before the element. 2. Write the symbol of the noble gas K in brackets. 3. Write the remaining configuration after the brackets. Al  MORE EXAMPLES 🔴Identify the atoms with the following abbreviated configuration: 1. [He] 2s2 2p2 = 6. [Xe] 6s2 4f5 = 2. [Ar] 4s2 3d10 4p2 = 7. [Ar] 4s2 3d10 4p3 = 3. [Ne] 3s2 3p2 = 8. [Kr] 5s1 = 4. [Xe] 6s2 4f14 5d9 = 9. [Rn] 7s2 5f14 6d3 = 5. [Kr] 5s2 4d9 = 10. [He] 2s2 2p5 =  LESSON SYNTHESIS 1. The Quantum Mechanical Model is the basis of the modern understanding of the atom. 2. The main idea of this model was to disregard the idea that an electron would follow a definite path around the atomic nucleus. Instead, electrons move in space surrounding the atomic nucleus, and electrons in an atom have only a quantized value of energy. These electrons are located within certain regions called orbitals. 3. An orbital is an area where an electron is most likely to be found. There are four basic types of orbitals. These are the s, p, d, and f orbitals. 4. Electron configuration is the distribution of electrons of an atom in orbitals. The symbols used for writing the electron configuration start with the energy level number followed by the type of orbital and finally the superscript that indicates the no. of electrons in the orbital. 5. The Aufbau principle states that in the ground state of an atom or ion, electrons fill subshells of the lowest available energy before subshells of higher energy.  REFERENCES READ AND PREPARE FOR THE NEXT LESSON Chapter 7 pages 270 -277