1. Pick up a picture from teacher 2. Conduct research using your phones and textbook to find: birth date- death date country, state, city of origin major contributions to chemistry year of major contribution fun/ interesting fact 3. Create a tombstone for your chemist using the picture and information you gathered. Make it neat! 4. Present your chemist to the class by performing a skit, poem, or rap. In pairs… “ Dead Chemists Society”
Atomic Theory
Particle theory supported as early as 400 B.C Democritus- coined term atom (means indivisible) Aristotle- all matter was continuous Ideas accepted for nearly 2000 years Modern definition of element accepted by 1700s Elements known to combine to form compounds Do they always combine with the same ratio when forming particular compounds? Improved technology leads to accurate measurements of elements and compounds Leads discovery of several basic laws Foundations of Atomic Theory
Law of conservation of mass Matter can neither be created nor destroyed during ordinary chemical reactions Law of definite proportions A particular chemical compound will always contain the same elements in the same proportions, no matter what the sample size or source Law of multiple proportions If two or more different compounds are composed of the same elements then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small numbers CO vs. CO 2
All matter is composed of extremely small particles called atoms Atoms of a given element are identical in size, mass, and other properties Atoms of different elements differ in size, mass, and other properties Atoms cannot be subdivided, created, or destroyed Atoms of different elements combine in simple whole- number ratios to form compounds In chemical reactions, atoms are combined, separated, or rearranged Dalton’s Atomic Theory
What is true from Dalton’s theory: All matter is made of atoms Atoms of one element differ in properties from atoms of another What was modified from Dalton’s Theory Atoms can be subdivided Modern Atomic Theory
Mendeleev- created first periodic table, arranging elements by atomic mass and chemical properties Was able to predict the discovery of new elements based on chemical properties Some elements, however could not be put in order by atomic mass Moseley- elements could be better organized if arranged by atomic number Mendeleev and Moseley Organizing the elements
WHO : who is the video talking about? WHAT : what did they discover? HOW : how did they discover it? Describe their experiment. Rutherford Thompson Then watch this Just how small is the atom? Watch 2 videos and find the following information: