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By 1869 how many elements had been discovered? 63 Dmitri Mendeleev discovered a set of __________ applied to all the elements. patterns How did Mendeleev arrange the elements? in order of increasing atomic mass What is atomic mass? the average mass of all the isotopes of an element In 1869 _________ published the first periodic table with ______ elements and three missing elements? Mendeleev, 63 What are the two differences between Mendeleev's table and the modern periodic table? (1) new elements have been added as they were discovered (2) arranged in order of atomic number , NOT atomic mass Who discovered a way to measure the positive charge ( the atomic number) on an atom's nucleus? Henry Moseley in 1913 The properties of an element can be predicted from its location in the __________ _______ periodic table The _________ of an element can be predicted from its location in the periodic table properties The horizontal rows are called _________ periods From left to right, the properties of elements in a period change in a _________ pattern From left to right the _________- of elements in a period change in a pattern properties The verticals columns are called _________ groups What are groups in the periodic table sometimes called? families THe elements in the same group have ________ characteristics similar What are the four things (from top to bottom) that are included in each square for an element? (1)atomic number (number of protons), (2) chemical symbol (3) name (4) atomic mass WHere do the elements come from? stars Like many stars, the sun is made of mostly which element? hydrogen The hydrogen is at high pressure and extremely high temperatures and it's state of matter is _______ plasma What is plasma? a state of matter that is gas-like and is made of free electrons and nuclei of atoms without electrons When these nuclei in the plasma collide they join together and form larger nuclei and release huge amounts of ___________ energy What is nuclear fusion? when smaller nuclei combine and form larger nuclei - in stars In the sun when isotopes of hydrogen fuse they make nuclei of ______ helium What is the most important source of energy in the sun? When hydrogen fuses to form helium nuclei and energy is produced Helium builds up in the sun's core and one or two helium nuclei fuse and form _________ beryllium WHen a helium nucleus fuses with a beryllium nucleus what is formed? carbon Fusion keeps going until the core of the star is almost all _________ iron. What do we call it when a star explodes? a supernova A supernova provides enough energy to create the ________ ____________ heaviest elements What happens to the heavy elements that a supernove creates? they are blown of into space as the star burns out THe matter in the sun and its planets originally came from a gigantic _________ supernova