atom2[1].jpgElements and Atoms

By Chris C. and Matt C.

Compunds and mixtures
Facts about atoms
Atomic theories and models


To summarize the basic knowledge we have on elements, this is what's excepted as fact. Matter is made up of elements. Elements are the purest substance, and cannot be broken down in another one. Elements like, for example, gold, hydrogen, argon, indium, and nickel are all made of atoms. All elements are made of atoms. An element can only have one kind of atom in it. (David V. Frank, John G. Little, Steve Miller)

Compounds and Mixtures

Have you ever wondered what happens when you mix sugar or salt into water? When the salt dissolves, the water becomes a compound. A compound is a substance made of at least two elements chemically combined in a fixed ratio. They are written like H2O, which is when hydrogen and oxygen combine to make the compound of water. Salt from seawater is a compound, which is always at a ratio of 39.3% to 60.7%(sodium to chlorine). A mixture is similar, but not the same. A mixture is when at least two substances combine, but not chemically. For example, air is a mixture of compounds and elements. These gases are together but not chemically combined, which is what makes it a mixture, not a compound.(David V. Frank, John G. Little, Steve Miller)

Facts About Atoms

Atoms are the absolute smallest part of an element. This was first proposed by the Greeks. Democritus named them "atomos". Atoms were not excepted until the late 18th century. However the Greek's believed that elements were air, earth, fire, and water. This is illustrated in the elements skate logo. (David V. Frank, John G. Little, Steve Miller)

Atomic Theories and Models

John Dalton proposed the first models of atoms as well as an atomic theory. He related atoms to hard, unbreakable balls. Dalton theorized that atoms cannot be changed or created nor destroyed. He also theorized that an element has only one kind of atom, all of which are exactly alike, but different then those in a different element.
In 1897 J.J. Thomson discovered electrons. His model was the same as Dalton's, with the atom positively charged and with negatively charged electrons. In 1911, one of Thomson's students, Rutherford, discovered the atom has a positively charged nucleus, where the atom's mass came from. He named the particles that were positively charged "protons". In 1913, a student of both Thomson and Rutherford remastered the model. His resembled a planet with many moons. Then, in 1920, the model was redone. Scientists concluded that electrons were not in orbit like planets, but instead they were arranged by energy level. The higher the energy level, the closer you are to the nucleus.
In 1932, James Chadwick made the latest change to the modern model. He discovered the neutron, a particle without any electric charge. (David V. Frank, John G. Little, Steve Miller) (the link to our voki)

Work Cited
Frank, David, John Little, and Steve Miller. Chemical Interactions. Pearson Prentice Hall, 2009. 98-102
Newmark, Ann. Chemistry. Red Kite Books, 1993. Print.
Ardley, Neil. The World of the Atom. Franklin Watts, 1989. Print.
"atoms." Web. 17 May 2011. <>.
"elemnt skate logo." Web. 17 May 2011."atoms." school tube. Web. 18 May 2011. <>.