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Atom Atoms are made up f 3 smaller particles: Protons: Found in the nucleus Neutrons: Found in the nucleus Electrons: found outside the nucleus Protons & neutrons both have a mass = 1 atomic mass Electrons have a mass of 1/2000 very tiny Atomic number is the number of protons in an atom atomic number/ number of protons atomic mass Atomic mass: this is the mass of the particles found in the nucleus/ always a decimal Mass number: the atomic mass round to the nearest whole number Neon mass number is: 20 Ex: Neon Protons: 10 (look at atomic number to find) Electrons: 10 (same number of protons) Neutrons: 10 ( Mass # = #of protons + # Neutrons) 20 = 10 +10 Isotopes: 1. Atoms of the same element with a different number of neutrons 2. This different number f neutrons gives those atoms different Atomic masses 3. the Atomic mass of an element is based on the averages of its Isotopes. Ex: Energy levels: Theses are the levels where the electrons are found around the nucleus of the atoms. Higher the levels # the more energy Each level holds a certain number Maximum # is only achieved in the 1st 4 levels Outer level or last level is the one that is involved in bonding atoms together to form compounds Compound- 2 or more elements/ forms a new substance EX: Hydrogen + oxygen= combines to form water EX: H2SO4 2 hydrogen atoms 1 sulfur atom 4 oxygen atoms 2NaCl 2 sodium atoms 2chlorine atoms (coefficient like 2 means multiply everything by 2) Valance electrons: the # of elements found in the outer or last level Bounding of atoms Maximum # of electrons found in these level are 8 except in the 1st level it is 2 Lewis Electron Dot Diagram: Electrons are found outside the nucleus Spin around the nucleus in different energy levels The electrons in the outer most level- take part in making compounds (Valence electrons) Determine Valence: There are 8 columns/ maximum # of valance e- is 18 Ex: Neon valance is 8/ it’s in the 8th column Radioactivity: 1. Nuclear Fission-split the nucleus into 2 smaller nuclei or roughly equal mass 2. Nuclear Fusion: joining together 2 nuclei of smaller masses into 1 large-mass nucleus Need temp. over 1 million Celsius Stars/sun 3. nuclear Transmutation: when one element changes into another element Ex: U-238 Atomic # 92 Alpha decay: Nucleus release 2 protons + Helium nucleus 2 neutrons o 4 Amu charge is + Th-234 atomic # 90 2. Beta decay-release an e-from nucleus atomic # increases by 1 mass = doesn’t change 3.Gamma decay- a release of huge quantities of energy by the nucleus need to look at examples in notes