PHYSICAL SCIENCE REVIEWER ORIGIN OF ELEMENTS KEY STAGES IN BIG BANG THEORY Singularity Inflation Formation of Matter & Anti-Matter Cancellation of Matter & Anti-Matter Cooling Down of Universe Big Bang Nucleosynthesis Recombination Dark Ages Formation of Cosmic Bodies - WHAT'S FORMED AFTER DEUTERIUM? - all of the remaining free neutrons in the universe were rapidly bound up in deuterium nuclei - H and He SPECIFIC NUCLEAR REACTIONS TYPES OF NUCLEAR REACTIONS 1. ALPHA DECAY - loss of an alpha particle 2. BETA DECAY - loss of a beta particle BIG BANG THEORY PERSONALITIES • Einstein - universe is static - "relativity theory" • Hubble - further away the galaxy, the greater the redshift of its spectral lines - "redshift" hubble's telescope • Lemaitre - the universe was smaller yesterday than today - "hypothesis of the primeval atom" • Gamow - high density caused rapid expansion - "hot big bang" - H and He are the first elements formed NUCLEOSYNTHESIS (Nucleus Formation) CREATION OF PRIMORDIAL ELEMENTS - in the early universe, once the deuterium bottleneck was cleared, newly formed deuterium could undergo further nuclear reactions to form higher elements Nuclear Fusion - nucleus combines Nuclear Fission - nucleus splits 3. GAMMA RADIATION - emission of gamma ray 4. POSITRON EMISSION - conversion of proton into a nucleus 5. ELECTRON CAPTURE - drawing of an electron into an atom's nucleus 6. BOMBARDMENT OF ALPHA PARTICLE - addition of alpha particle F O R M AT I O N O F H E AV Y ELEMENTS FORMATION OF A STAR 1. NEBULA - uneven distribution of H and He allowed gravity to act in the areas of higher concentration to initiate the "clumping of matter" 2. PROTOSTAR - high velocity resulted to increase in temperature - atoms became more tightly packed Page 1 ! of 7 ! • Stellar Nucleosynthesis - temp & density continue to increase until nuclei reached the "flash point" - once it reaches the flash point, this allows strong nuclear force to bind with smaller nuclei, forming a more massive nucleus this is called FUSION 3. MAIN SEQUENCE STAR - proton to proton chain - H and He - CNO Cycle 4. RED GIANT STAR - triple alpha process - He to C and C to Fe - production of elements stopped when Fe was formed - Fe nuclei are the most stable of all because when they undergo reaction, they don't release energy, they absorb 5. SUPERNOVA - after the star exhausted the nuclear fuel, its core started to collapse that lead to the explosion of the star - explosion release huge amount of nuclear energy & produced other elements heavier than iron 6. BLACKHOLE - a region in space where the pulling force of gravity is so strong that light is not able to escape UNIVERSALITY OF THE LAWS OF PHYSICS 3. ARISTOTLE - noted that there were stars in Egypt that could not be seen on other parts of the earth 4. ERASTHOTHENES - estimated the circumference of earth MOTIONS OF THE EARTH • AXIAL PRECESSION a. Precession - change in orientation of the rotational axis of any rotating body b. Precession of The Equinoxes - change in orientation of the earth's axis, happens every 26,000 years • ANUAL MOTION a. Revolution - motion of a body along a path around some point in space - anual motion of earth is one complete revolution around the sun Perihelion - time in January when Earth is closes to the sun Aphelion - time in July when Earth is farthest from the sun b. Ecliptic - sun's apparent annual path among the constellations c. Zodiac Constellations - constellations on the celestial sphere through which the ecliptic passes THE SPHERICAL EARTH 1. PYTHAGORAS - started the idea of spherical earth 2. PLATO - educated his students about the sphericity of the earth but made no justifications • DIURNAL MOTION - daily motion of stars & other celestial bodies across the sky - rotation is the turning or spinning of a body on its axis - celestial objects (particularly the sun) appear to rise in the East & set in the West which is a result of the earth's rotation on the axis from west to east Page 2 ! of 7 ! TWO MEASUREMENTS FOR ROTATION: 1. Mean Solar Day - time interval from one noon to the next, about 24 hours 2. Sidereal Day - time it takes for the earth to make one complete rotation with respect to a star other than the sun which is 23 hours, 56 minutes, 4 sec. MODELS OF THE UNIVERSE 1. EUDOXUS' MODEL - homocentric model - celestial sphere shares one common center and that's the earth - 1st model of geocentric model - 27 celestial spheres, 5 planets 2. ARISTOTLE'S MODEL - geocentric model - proved that the earth is spherical - earth is fixed at the center of the solar system & everything revolves around it - all stars are fixed points which rotate on a single celestial sphere - 56 celestial spheres - prime mover drives the motion of the planets 3. ARISTARCHUS' MODEL - heliocentric model - 1st to place the sun at the center of the universe - sun and stars are fixed - earth is revolving around the sun in circular orbit 4. PTOLEMY'S MODEL - geocentric model - shows the deferent (circular path in which planets move) and epicycle (circles where planets move) - proposed the equant (a point close to the orbit's center) - planets revolved around the sun - earth spins on a tilted axis 6. TYCHO'S MODEL - geoheliocentric model - brahe plotted all his observations of the heavens using instruments of his own design - all the predictions he made were much more accurate - both helio and geo with planets revolving around the earth 7. KEPLER'S MODEL - heliocentric model - planetary orbits were based on geometric shapes (ellipse) - planets movement around the sun were elliptical - the close the planets were to the sun, the faster they orbited - able to predict motions of the universe fairly & accurately KEPLER'S LAW OF P L A N E TA R Y M O T I O N 1. ELLIPSES - orbit of a planet is an ellipse, with the sun at one focus 2. EQUAL AREAS - planets travel equal areas of space in equal periods of time - planets travel faster during perihelion and travel slower during aphelion 3. HARMONIES - the larger the planet's orbit, the longer the revolution - the square of the revolutions of the planet are directly proportional to the cubes of their average distances 5. COPERNICUS' MODEL - heliocentric model - celestial motions are uniform, infinite Page 3 ! of 7 ! K I N E M AT I C S & D Y N A M I C S • KINEMATICS - describes motion in terms of displacement, velocity & acceleration • SCALARS - quantities that are fully described by a magnitude (numerical value & units) • VECTORS - quantities that are fully described by both a magnitude & a direction SC A LAR V E CTOR Distance Displacement Spe ed Velocity A cceleration • DISTANCE - how much ground an object has covered during its motion - how far you've travelled, regardless of direction • DISPLACEMENT - how far out of place an object is - where you are in relation to where you started • RESULTANT - sum of two of more vectors FORMULAS TO REMEMBER: A plane flying due north at 100m/s is blown by a 500m/s strong wind due east. What is the direction of the plane? 500m/s 100m/s = 5m/s • SPEED - how fast an object is moving - rate at which an object covers distance • VELOCITY - how fast & which way - rate at which position changes • INSTANTANEOUS SPEEED/VELOCITY - speed or velocity at any given instant (a particular moment) in time • AVERAGE SPEED/VELOCITY - the average of all instantaneous speeds - ratio of the total distance covered & the total amount of time travelled • ACCELERATION - refers to the change in velocity of a moving object per unit of time FORMULAS TO REMEMBER: For uniformly accelerated motion: If distance is missing: If acceleration is missing: If final velocity is missing: If time is missing: • DYNAMICS - study of the causes of motion • FREE FALL - when an object falls under the influence of gravity alone - all objects falling near earth's surface fall with constant acceleration • ACCELERATION DUE TO GRAVITY - symbolized by g - g = 9.80m/s - always directed downward - ignoring air resistance & assuming g doesn't vary with altitude over short vertical distances, free fall is constantly accelerated motion = = 78.69 east of north Page 4 ! of 7 ! FORMULAS TO REMEMBER: • PROJECTILE MOTION - motion of object in two dimensions - acted by gravity alone (no air resistance) - path a projectile follows is trajectory FORMULAS TO REMEMBER: 3. LAW OF INTERACTION - for every action there is an equal and opposite reaction - whenever an object exerts a force on a second object, the second object exerts an equal & opposite force on the first object FORMULAS TO REMEMBER: Horizontal Distance Horizontal Velocity Vertical Distance • MOMENTUM - vector quantity - fully described by magnitude & direction FORMULAS TO REMEMBER: Vertical Velocity Time of Flight Max. Height Reached Horizontal Range NEWTON'S LAW OF MOTION • Sir Isaac Newton - only 25 when he formulated most of his discoveries in math & physics 1. LAW OF INERTIA - an object remains at rest unless acted on by an external unbalanced force • Mass - quantitative measure of inertia • Force - action exerted upon by a body 2. LAW OF ACCELERATION - the acceleration of a body is directly proportional to the net force acting on the body & inversely proportional to the mass of the body - the greater force, the greater acceleration - the greater mass, the smaller acceleration • LAW OF MOMENTUM CONSERVATION - momentum is neither lost or gained - when two bodies collide with one another, the total energy remains constant - momentum is always conserved in collisions TYPES OF COLLISIONS: 1. PERFECTLY INELASTIC - 2 objects stick together after the collision - final velocities are the same 2. ELASTIC - 2 objects bounce after the collision - they move separately 3. INELASTIC - 2 objects deform during the collision - total kinetic energy decreases - but the objects move separately after FORMULAS TO REMEMBER: • Gravity - the force that pulls objects towards each other Page 5 ! of 7 ! • IMPULSE - change in momentum FORMULAS TO REMEMBER: ]\\ ELECTRON DISTRIBUTION & O R B I TA L D I A G R A M • ELECTRON CONFIGURATION No. of Electrons Energy Level Type of Orbital (Subshell) • ORBITAL DIAGRAM Oxygen 1s 2s 2p - boxes & arrows represents the orbitals & Noble Gas Electron Configuration - shorthand configuration - for elements with high atomic number - use of core symbols - written as element symbol inside bracket - represented by the noble gas that belongs to the row before that of the element questioned Elements Starting in The "D" Block Special Rules - elements from H to Ca have no conflict with Aufbau Principle - elements starting from Scandium starts to fill the d-block - these elements follows the Aufbau Principle in filling the orbitals, but once you get to Scandium, the energy of the 3d orbitals becomes slightly less than that of the 4s so the electron configuration will be arranged differently - Cr and Cu are exemption to the Aufbau principle electrons - the up & down orientation of arrows represents 2 magnetic spins of the electrons RULES IN ELECTRON DISTRIBUTION Aufbau Principle - electrons should occupy first the orbitals with lower energy before those with higher RULES IN ORBITAL DIAGRAM Pauli's Exclusion Principle - no two electrons in an atom can possess the same set of quantum numbers Hund's Rule of Max. Multiplicity - the most stable arrangement of electrons in subshells is the one with greatest number of parallel spins QUANTUM NUMBERS QUANTUM MODEL OF THE ATOMS • BOHR MODEL - one dimensional model that describes the distribution of electrons in the atom - described the size of the orbit, which was described by the n quantum number • SCHRODINGER'S MODEL - allowed the electron to occupy three dimensional space - three quantum numbers, to describe the orbitals in which electrons can be found - three coordinates that come from this model wave equations are: principal (n) - size angular (l) - shape magnetic (m) - orientation Quantum Numbers - describe the orbitals in which the electrons can be found Page 6 ! of 7 ! 1. PRINCIPAL QUANTUM NO. (N) - describes size & energy of the orbital High n - high energy of an orbital - larger the orbital, further from the nucleus Low n - low energy of an orbital - smaller the orbital, closer to the nucleus 2. ANGULAR QUANTUM NO. (L) - describes the shape of the orbital - has integral numbers from 0 to n-1 l = 0 - s orbital l = 2 - d orbital l = 1 - p orbital l = 3 - f orbital 3. MAGNETIC QUANTUM NO. (M) - describes the orientation of the orbital in space - has integral values between -/ and /, including 0 if / = 1 (p orbital), m/ = -1, 0 or 1 if / = 2 (d orbital), m/ = -2, -1, 0, 1 or 2 4. ELECTRON SPIN QUANTUM NO. (Ms) - spinning motion of an electron when placed in an external magnetic field - an orbital can hold only 2 electrons & they must have opposite spin s C. DMITRY MENDELEEV - published the idea firs (Julius Lothar's) - improvement of Newland's work - use of "eka" = first D. HENRY GWYN MOSELEY - atomic number = no. of protons - determines the order of elements in the table • PERIODS / SERIES - are arranged horizontally across the periodic table - rows 1 to 7 - these elements have the same number of valence shells = energy level • FAMILY / GROUP - arranged vertically down - group 1 to 18 or 1 to 8 A,B - these elements have the same number of electrons in the outer most shells, the valence shells LEWIS DOT SYMBOL - named after Gilbert Newton Lewis - consists of the symbol of an element - surrounded by 1 or more dots each dot corresponds to every valence electron in an atom • VALENCE ELECTRONS - electrons in the outermost principal quantum level of an atom P E R I O D I C TA B L E A. JOHN A.R. NEWLANDS - law of octaves - arrangement based on atomic masses & regularities every 8 elements B. JULIUS LOTHAR MEYER - proposed arrangement of elements based on atomic masses Page 7 ! of 7 !
