https://padlet.com/23arlethc101/74tr9s67hg81zntf Made by Arleth <3 en-us 2021-02-04 20:15:39 UTC 2026-01-26 15:13:21 UTC hello@padlet.com https://padlet.net/icons/png/1f973.png 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166344974 Greek philosopher Democritus, who was born in the year 460 B.C.E and died in the year 370 C.E., introduced the atomic theory. He said that the atom is the basic building block of matter. He believed that atoms were tiny, uncuttable, solid particles that are surrounded by empty space and constantly moving at random. He also believed that different kinds of matter consists of different arrangements of atoms.

]]> 2021-02-04 22:31:04 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166344974 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166354215 English scientist John Dalton, who was born on September 6, 1766 and died on July 26, 1844, proposed the idea that all matter is made of indestructible and invisible atoms. His law says that all atoms of an element are identical, for different elements, the atoms have different weights of a simple whole number, and that atoms can't be created nor destroyed.]]> 2021-02-04 22:35:44 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166354215 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166363928 British scientist Sir Joseph John Thomson, who was born on December 18, 1856 and died on August 30, 1940, discovered electrons by using a cathode ray tube. He proposed the idea that atoms consist both of positive and negative charged particles. He also created the a model of the atom that was made up of positive and negative charges, present in equal amounts so that an atom would be electrically neutral. ]]> 2021-02-04 22:40:57 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166363928 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166376476 British scientist Ernest Rutherford, who was born on August 30, 1871 and died on October 19, 1937, suggested the nuclear structure of the atom. He theorized the Rutherford model of the atom, of which exists a nucleus containing the majority of the atom's mass and all of its positive charge. He showed that atoms are mostly made of empty space and discovered this by firing helium nuclei at a thin sheet of gold foil.]]> 2021-02-04 22:47:53 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166376476 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166391487 Danish scientist Niels Bohr, who was born on October 7, 1885 and died on November 18, 1962, proposed a theory for the hydrogen atom. He believed that electrons should move around the nucleus but only in prescribed orbits. He thought that electrons are arranged in a circular orbit around the nucleus in circles (shells). He showed that electrons do not move gradually from one shell to the next, they seem to instead disappear from 1 shell and quickly disappear in another. ]]> 2021-02-04 22:56:44 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166391487 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166400005 Austrian-Irish physicist Erwin Schrodinger, who was born on August 12, 1887 and died on January 4, 1961, developed the Bohr model more, where he was able to find the electrons in certain positions. He created a model that was named the quantum mechanical model, this has an electron cloud circling the nucleus, the denser the cloud in one area is, the more likely electrons are going to appear there.]]> 2021-02-04 23:01:36 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166400005 23arlethc101 https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166409607 African American nuclear chemist James Harris, who was born on March 26, 1932 and died on December 12, 2000, co-discovered elements 104 (rutherfordium) and 105 (dubnium) on the periodic table. He was the first African American to discover an element. ]]> 2021-02-04 23:07:19 UTC https://padlet.com/23arlethc101/74tr9s67hg81zntf/wish/1166409607