Q2W1-SC-ATOMS-ELECTRON-CONFIGURATION PDF

Module 1 Science 9 Quantum Quarter 2 Mechanical Model of an Atom R C Proposed by Ernest Rutherford as a result of his _________1. alpha-scattering experiment. E A Also known as the Billiard-ball model. _______2. B _______...

Module 1 Science 9 Quantum Quarter 2 Mechanical Model of an Atom R C Proposed by Ernest Rutherford as a result of his _________1. alpha-scattering experiment. E A Also known as the Billiard-ball model. _______2. B _______3. The atomic model proposed by J.J. Thomson with a V positive solid sphere and negative particles scattered throughout the atom. I D _______4. The atomic model proposed by Neils Bohr with orbits where electrons are moving. E D _______5. This atomic model is also known as the “planetary model” of the atom W  The Basic Structure Of An Atom Review of Previous ELECTR ON Lesson Pre-activity 2: ATOM NEUTR PROT MAKES US ALL MATTER! ON ON SHEL L NUCLEU S  PROTO NEUTRO PROTO NS NS NS ELECTRO NS CAPIT AL LOWER CASE  VOCABULARY WORDS  Quantized - refers to the fact that energy can only be absorbed and emitted in a range of allowable values rather than with any possible value.  Energy level – orbits or shells which assigned each a number: n=1, n=2, n=3, etc. or letters (K, L, M, N, O, etc. ).  Excited state- If the electron received extra energy, it can jump into a higher energy level,  Ground state- The electron in the excited state can return to its original lower energy level by releasing discreet amount of energy in the form of light.  Atomic orbital - is the region around the nucleus where the electron is most likely to be found  Atom itself is not visible to the naked eye. So, for you to Lesson1 understand more how the structure of atoms affects the physical and chemical properties of an object, let’s start focusing on what is visible. Electrons In order for the objects to be visible, light is needed. It is characterized by wavelength and amplitude. and Energy Level The crest is the highest point of a wave while the trough is the lowest point. The distance between two crests (or two troughs) is the wavelength. If a horizontal line is drawn from the crest and another from the trough, the distance between these two lines is the amplitude.  Each color of light has a specific wavelength. Among the visible light, red light has the longest wavelength and has the lowest energy. Violet light has the shortest wavelength and has the highest energy.  When compounds of different elements are heated over a flame, it comes to a point where the hot gaseous atom begins to emit light of a definite color.  Analysis of light given off by the vapors of elements can be done more precisely with an instrument called spectroscope.  With the use of spectroscope, one can detect a series of narrow lines or line spectrum on the light given off by an element. The spectral lines suggest different energy levels in an atom. Atomic Model & Theory Timeline  Rutherford’s nuclear atomic model describes the atom as mostly empty space. Its mass is concentrated in the nucleus where protons and neutrons are found. However, it could not explain the chemical properties of elements. The flame test is a phenomenon that led to the development of the atomic model by Neils Bohr. It showed that atoms, specifically the electrons have connection with energy. Upon heating the metal salts, change in the energy of the electron took place which can be physically observed upon color emission in the flame. Niels Bohr postulated that the electrons in an atom are found in certain distances from the nucleus. These “distances” are related to the energy that an electron has, and these are called energy levels. Main energy levels or shells Niels Bohr, a Danish scientist, explained this line spectrum while developing a model for the atom: The Bohr model shows that the electrons in atoms are in orbits of differing energy around the nucleus (think of planets orbiting around the sun).  Bohr used the term energy levels or shells (assigned each a number: n=1, n=2, n=3, etc. or letters - K, L, M, N, O, etc. ) to describe these orbits of differing energy. Electrons in each orbit have a definite energy, which increases as the distance of the orbit from the nucleus increases. He said that the energy of an electron is quantized, meaning electrons can have one energy level or another but nothing in between. The energy level an electron normally occupies is called its ground state. But it can move to a higher-energy, less-stable level, or shell, by absorbing energy. This higher-energy, less-stable state is called the electron’s excited state.  After it’s done being excited, the electron can return to its original ground state by releasing the energy it has absorbed, as shown in the diagram.  Sometimes the energy released by electrons occupies the portion of the electromagnetic spectrum (the range of wavelengths of energy) that humans detect as visible light. Slight variations in the amount of the energy are seen as light of different colors.  Metal salts when heated The colors in the flame is an produce different colors indication that definite energy because of the absorption transformations occur inside the of heat from the flame. atom emitting light. It follows that electrons must occupy orbits of The outermost particles fixed energy. (electrons) in the metallic element are responsible for The electrons are moving around the production of colored the nucleus in circular orbits. light. When an electron absorbed extra energy from an outside source (flame), the electron moves to a higher orbit. Colored light is emitted when the electron falls back to a lower orbit. This light is the difference between the energies of the two orbits involved.  The energy levels (orbits) of electrons are like the steps of a ladder. The lowest step of the ladder corresponds to the lowest energy level. A person can climb up and down by going from step to step. Similarly, the electrons can move from one energy level to another by absorbing or releasing energy.  A quantum of energy is the amount of energy required to move an electron from its present energy level to the next higher one. The amount of energy gained or lost by every electron is not always the same. The higher the energy level occupied by an electron, the easier it is for the electron to escape from the atom.  Lesson 2 Atomic Orbitals and Electron  Luksong tinik is one of our traditional Configuration games which originated in Cabanatuan city. As the height of the barrier (tinik) increases, Why do players move away before jumping? Relate your answer to the energy of an electron as its distance from the nucleus increases.  Two pictures of electric fan were shown. In the left photo, the fan is turned off. In the right, it was running at high speed. In the right photo, the blades are moving too fast for you not to be able to see the individual blades distinctly unlike if blades are not moving. In some ways, rapidly moving fan blades are similar to the electrons moving about the nucleus of an atom. Like fan blades, electrons move very quickly, and we can never tell exactly where they are. If that’s the case, how can we represent electrons in models of the atom?  Louis de Broglie – he said that Quantum electron that is said to be a particle Mechanical could actually also be considered as a wave Model of an Schrodinger – used the idea of de Atom Broglie and made a mathematical calculations to determine the exact location of the electron around the nucleus Heisenberg - “Uncertainty Principle” meaning that the exact location of the electron cannot be exactly known  These three-scientists believed that there is only a probability that electrons can be found in a three-dimensional region in space around the nucleus which is called atomic orbitals. Quantum Mechanical Model of an Atom  An atomic orbital is the region It would be impossible to around the nucleus where the plot a definite path or orbit electron is most likely to be for the moving electrons. At found. The atomic orbital least, we can only guess the serves as the “house” of the most probable location of the electron. It can accommodate a electron to be within a certain maximum of 2 electrons. volume or region of space  Aside from the main energy surrounding the nucleus. levels and atomic orbitals, there are also energy sublevels as shown by the finer lines in the atomic emission spectra of elements.   The way in which electrons are distributed in the different orbitals Electron around the nucleus Configurati on   In the electron configuration of 1s2, 1 refers to the main energy level occupied by the electron, s denotes the Electron kind of orbital and the superscript 2 for the number of electrons in the orbital. Configuration The main energy level also tells as the number of sublevels. The name of the sublevel is also the same with the name of the orbital. No. of Energ 1s 2 Electro ns y Level Orbita l Type Figure A. A sublevel is an energy level defined by quantum theory. In chemistry, sublevels refer to energies associated with electrons. In physics, sublevels may also refer to energies associated with the nucleus. Meaning Maximum e- s= (standard) 2 e- p= (principal) 6 e- d= (diffuse) 10 e- f= (fundamental) 14 e- The orbital diagram is a type of diagram which shows the distribution of electrons in the orbitals of an atom and indicates the spin of those electrons. It shows which orbitals are filled and which are partially filled. We use arrows to represent electrons. The direction of the arrowhead (upward or downward) indicates the spin of the electron.  For every energy level (n), there are different sublevels as presented in Figure B.  32 1 7  ACTIVITY 2: SUBLEVELS OF ENERGY LEVELS Part 1: If you have 7 energy levels within the atom, and you have to label them with letters beginning with K, label each energy level (1-7) with letters following the alphabet. Copy and complete the figure A.  Why is it  The electron configuration of an atom important to determined the chemical reactions the atom can participate in and the kinds of study molecules that atoms can combine into to form more complicated substances. electron  It can also be used to represent an atom configuration that has ionized into a cation or anion by compensating with the loss or gain of ? electrons in their subsequent orbitals  Help make predictions about how certain elements will react (an atom is most reactive when its valence shell is not full and most stable when its valence orbitals are full. ACTIVITY 3: LET’S RIDE ON A SUBLEVEL! Three Rules Applied in Deriving the Electron Configuration. 1. Aufbau’s Principle - also known as the “building-up” principle, states that electron's occupy orbitals in order of increasing energy. EXAMPLE: a. Li-3: 1s2 Write the 2s1 electron configuration of b. Na-11: 1s2 a. Li-3 2s2 2p6 3s1 b. Na-11 2. Pauli’s Exclusion Principle - Electrons occupying the same orbital must have opposite spin ↑↓. 3. Hund’s rule of Multiplicity -When electrons enter a sublevel with more than one orbital, they will spread out to the available orbitals with the same spin before pairing.  The Quantum Mechanical Model views an electron as a cloud of negative charge having a certain geometrical shape. RECAP! This model describes the atom as having a nucleus at the center around which the electrons move. Moreover, this model defines the region in space where the electron is most likely to be found. The information about the energy of the electron is being described as well by this model.  The model also describes the region of space around the nucleus as consisting of shells. This shells are called principal or main energy levels. The principal/main energy levels or shells may have one or more sublevels. These sublevels are assigned with letters: s, p, d and f. The described probability is a mathematical function that describes a cloud-like region where the electron is likely to be found called an orbital.  An electron configuration consists of the symbol for the occupied subshell with a superscript indicating the number of electrons in the subshell. An orbital diagram consists of a box representing each orbital and an arrow representing each electron.  Electrons are distributed in different energy level according to the following principles: ✔ Aufbau Principle-available atomic orbitals are occupied by electrons in the order of increasing energy starting from the lowest. ✔ Pauli’s Exclusion Principle (Wolfgang Pauli)- A maximum of two electrons can occupy an atomic orbital. No two electrons in an atom can have the same set of four quantum numbers. ✔ Hund’s Rule of Multiplicity- Orbitals of equal energies are filled up singly first before pairing up.  1. ___________ atomic model describes the atom like a solar system, Lesson where theBohr’s electron is found only in specific circular paths, or orbits around the nucleus. Summary 2. Electrons in each orbit has ________ energy. fixed 3. An electron can jump to a higher energy level by gaining energy and return to a lower energy level by releasing energy in the form of ________. light 4. The Bohr model was later replaced by a model of the atom that electrons showed that __________are not limited to fixed orbits around the nucleus. Schrodinger 5. _____________ formulated a mathematical equation that describes the behavior of the electron. The solution to the equation is used to calculate the probability of finding the electron at a particular region in space around the nucleus called ________________. Atomic orbital 6. TheQuantum __________________ model of the atom describes the atom as mechanical having a nucleus at the center around which the electrons move. This model describes a region in space where the electron is most likely to be found. 7. The distribution Electron of electrons in the different atomic orbitals is called _____________________. configuration For Listening And Active Participation !