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The simplest Matter. Sci 11.2. Atomic number:. Number of protons in an atom Ex: all Cl atoms have 17 p +. Question 1. Mass number:. sum of protons and neutrons in an atom Ex: 35 Cl (chlorine 35) 17 p + , 18 n 37 Cl (chlorine 37) 17 p + , 20 n. Question 2. Isotopes:.
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The simplest Matter Sci 11.2
Atomic number: • Number of protons in an atom • Ex: all Cl atoms have 17 p+
Mass number: • sum of protons and neutrons in an atom • Ex: 35Cl (chlorine 35) 17 p+, 18 n 37Cl (chlorine 37) 17 p+, 20 n
Isotopes: • Atoms of the same element with different numbers of neutrons • Ex: 35Cl, 37Cl, protium, deuterium, tritium p+ n p+ p+ n n Isotopes of hydrogen
Atomic mass (weight): • Average mass of isotopes of that element • Ex: 76% Cl is 35Cl, 24% is 37Cl avg. is 35.45 37Cl 24.2% 35Cl 75.8%
Metals: • Shiny or metallic luster • Good conductors of heat and electricity • Solids at room temp. (except Hg) • Malleable
Nonmetals: • 97% of your body • Usually not shiny • Lousy conductors • Many are gasses • brittle
Metalloids: • Characteristics of metals and nonmetals • used to make semiconductors
19 K 39.098 Atomic # Atomic symbol Atomic mass
term symbol, definition / description Element Electron Proton Neutron Electron cloud - matter made of only 1 kind of atoms - cannot be broken down to simpler substance - e-, negatively charged subatomic particles - outside nucleus, much smaller than a p+ - p+, positively charged subatomic particles - inside nucleus - n, neutral subatomic particles - inside nucleus n - areas around nucleus - where electrons are most likely found
Theorist type of experiment, how he pictured an atom Dalton Thomson Rutherford No experiments Atom is a hard sphere (like a BB) Magnet with cathode ray tube Electrons in atom like plums in pudding Shot alpha particles through gold foil Nucleus with protons and neutrons
term definition / description Atomic number Isotope Mass number Atomic mass Metals Nonmetals Metalloids - different for every element - number of p+, equal to e- if no charge - same element with different number of n - sum of protons and neutrons - average mass of all isotopes - shiny, good conductors of heat and elec. - solid at room temp, malleable/ductile - opposite metals, dull, bad conductors, brittle - in between metals and nonmetals - some shiny, some used for semiconductors