Properties The characteristics of the matter Matter classified by ____ and ____ State and composition classifies ____ 3 states of matter? Gaseous state, liquid state, and solid state are the 3 states of ____ Physical change A recognizable difference in the appearance of a substance without causing any change in its composition or identity Ex-water: snow-rain-humidity Physical property Observed or measured without changing the composition or identity of a substance Chemical properties Result in change of composition and can be observed only through chemical reactions Chemical reactions Chemical substance is converted to one or more different substance by rearranging, removing, replacing, or adding atoms. Ex: carbon dioxide + water -(light, chlorophyll)-> sugar + oxygen Chemical change (Synonymous w/ chemical reaction) Ex: process of formation of sugar Intensive property Property of matter that is <em>independent</em> of the <em>quantity </em>of substance Extensive property <em>Depends</em> on the <em>quantity</em> of a substance Pure substance Substance with only one component. Ex- Pure water:made only of particles containing 2 hydrogen atoms and 1 oxygen atom (H<sub>2</sub>O) Element A pure substance that cannot be changed into a simpler form of matter by any chemical reaction Compound Substance resulting from the combination of 2 or more elements in a definite, reproducible way Mixture Combination of 2 or more pure substances in which each substance retains its own identity. Ex: alcohol and water can be combined in a mixture. They coexist as pure substances because they do not undergo a chemical reaction. Mixture may be homogeneous or heterogeneous. Homogeneous mixture Mixture with uniform composition, its particles are well mixed, or thoroughly intermingled. Ex: Alcohol and water is described as a solution. Heterogeneous mixture Mixture with nonuniform composition. Ex: Salt and pepper Atom Basic structural of an element, which is the smallest unit of an element that retains the chemical properties of that element. Made of proton, neutron, and electron. Nucleus of atom Small, dense, positively charged region in the center of the atom. Composed of positively charged protons and uncharged neutrons. Protons (p<sup>+</sup>) Positive charge, in atom's nucleus. Neutron (n) Uncharged, in atom's neucleus Electron (e-) Negative charged, surrounding the nucleus. Low mass compared to protons and neutrons. Atomic number (Z) Equal to the number of protons in the atom Mass number (A) Equal to the <em>sum</em> of the number of protons and neutrons <question> Notations of atom? <sup>A</sup><sub>Z</sub>X<sup>E</sup> </question> A- mass number: # of protons & neutrons Z- atomic number: # of protons X- place for atom name E- place for charge (+/-) Isotopes Atoms of the same element having different masses <em>because they contain different number of neutrons</em>. (Have different mass numbers) Ex: carbon-12 (C-12), carbon-14 (C-14) Atomic Mass The <em>weighted </em>average of the masses of each isotope that makes up the element. Measured in <em>atomic mass unit</em> (<em>amu</em>) 1 amu = 1.66 x10<sup>-24</sup> grams (g) Dalton's Atomic Theory All matter consists of tiny particles called atoms An atom cannot be created, divided, destroyed, or converted to any other type of atom. Atoms of a particular element have identical properties Atoms of different elements have different properties Atoms of different elements combine in simple whole-number ratios to produce compounds (stable combination of atoms) Chemical change involves joining, separating, or rearranging atoms Ions Electrically charged particles resulting from gain or loss of electrons by an atom Anion Result of parent atom gaining one or more electrons Ex <sup>80</sup><sub>35</sub>Br<span style="color:#ff0000;"><sup>-</sup></span>: Bromine-80 <span style="color:#ff0000;">gains an electron<span style="color:#000000;"> </span></span> Cation Result when parent atom lose one or more electrons Ex: <sup>39</sup><sub>19</sub>K<span style="color:#0000ff;"><sup>+</sup><span style="color:#000000;">: Potassium-39 <span style="color:#0000ff;">loses an electron</span></span></span><sub></sub><span style="color:#000000;"></span> Quantum level Energy level: Orbit level an electron is at, thus fix energy at fix level Only allowed location for electrons Quantization Concept of fix energy and fix levels Absorb energy: closer neutron move farther from nucleus Release energy: farther neutron move closer to nucleus Quantum number Orbit identification number (n) Bhor Model 1st step to understanding an atom Electrons exist in specific energy states, transition requires specific amount of energy Quantum Mechanics Schroedinger's theory. Each level has sub level, which also has one or more atomic orbitals Principal energy levels Designated as n= 1,2,3,... 2(n)<sup>2</sup> ex: n=1, 2(1)<sup>2</sup>= 2, 2 electrons Sublevel ____is a set of energy-equal atomic orbitals within a principal energy level. Symbols in order: s<p<d<f 1st principal energy level (n=1) has 1 possible levels: 1s 2nd principal energy level (n=2) has 2 possible levels: 2s and 2p .... 4th principal energy level (n=4) has 4 possible levels: 4s, 4p, 4d, 4f Aufbau Principle Electron fill the lowest-energy orbital available first Energy configuration The arrangement of electrons in atomic orbitals Shorthand Electron configuration Bismuth Noble gas in bracket: Tin (Sn)<span style="color:#ff0000;">1s22s22p63s23p64s23d104p6</span>5s24d105p2 krypton; <span style="color:#ff0000;">[Kr]</span>5s24d105p2 as shorthand configuration for tin, since [Kr]1s22s22p63s23p64s23d104p6 Highlight valence electrons