History+of+the+Atomic+Model--Unit+2

(1) Who first thought of the idea of the atom? How was his idea accepted? Democritus, a Greek philosopher, was the first person to think of the idea of the atom. His idea was accepted because he proposed the idea that matter was not infinitely divisible and believed matter was made up of tiny individual particles called atoms. -Zamorria Pressley (Great job--Mrs. K)

Democritus was a Greek philosopher and was the first person to think of the idea of an atom.His idea was that matter was not infinitely divisible and that matter was made up of tiny individual particles called atomos, meaning atom. He also believed atoms could not be created, destroyed, or further divided. Democritus was laughed at for thousands of years on his theories, but eventually Dalton had the same ideas and was to use more advanced methods to refine and supports his and Democritus's hypothesis. -Melissa Ambrose (Great job--Mrs. K)

(2) Describe the postulates of Dalton’s understanding of the atom. The postulates of Dalton's atomic theory were used to explain earlier observations of the behavior of matter. His postulates were that all matter is composed of small, indivisible particles called atoms; all atoms of a given element are identical in mass and properties; compounds are formed by a combination of two or more atoms in definite arrangements in the ratio of small whole numbers; atoms are not created, destroyed or converted into other kinds of atoms during chemical reactions. They are just simply rearranged into simple compounds. Sagar Patel (Great answer--Mrs. K)

(3) What did Henri Becquerel discover? How did it happen?

(4) What did J.J. Thomson discover? Briefly describe how he did this. JJ Thomson discovered the election in a series of experiments that were designed to study the nature of electric discharge in a high-vacuum cathode-ray tube. Thomson discovered that the deflection of the rays by electrically charged plates and magnets were evidence of having a very large value for the charge-to-mass ratio. -Lindsey McManus (Good answer--Mrs. K.) J.J Thompson discovered the electron. Thompson did this by experiments focusing on electron discharge. He would right(?) down the deflection of the rays by the charged plates inside of his high-vacuum cathode-ray tube. He recorded the charge-to-mass ratio. Later, he determined the value of the charge itself. -Summer Hitt (Good answer--Mrs. K.) (5) What was J.J. Thomson’s model of the atom called? Describe it. JJ Thomson's model was called the Thomson Model of the "raisin bread model." He thought the an atom was like a sphere with postitive and negatively charged protons and nuetrons and they moved freely throughout the atom. -Jenna Reeves Thomson's model was call the "Raisin Bread Model." In the book it describes it to say it was like an atom that is like a sphere with positive and negative charged protons and it also contains neutrons that move freely throughout the atom. -Neha Patel. (Thomson said the atom was like a ball of positive charge (like the bread) with negative charges (like the raisins) scattered throughout--Mrs. K.)

(6) What did Millikan find out about the electron? Briefly describe his experiment. Millikan found out the mass and charge of an electron. He used the oil drop experiment which was when he saw if the oil drops would rise or fall. --Drew Walden (He was able to determine the charge by using the electrical plates to suspend the drops. Be sure you are familiar with his experiment--Mrs. K.)

Millikan discovered the mass and charge of the electron. He used the Oil Drop Experiment which used charged oil drops passed between plates of a parallel capacitor. A microscope observed the drops. The drops would quickly attain terminal velocity, but because of the plates they were made to rise rather than fall. The mass was determined by the radii of the oil drops. Erin F. (Very good description--Mrs. K.)

(7) Describe Rutherford’s gold foil experiment. Rutherford's experiment took place in 1911. He wanted to know how positively charged alpha particles interacted with solid matter. His experimental procedure was using a narrom beam of alpha particles and aim them at a sheet of gold that caused flashes of light.--Brittany Garrity (He found that most of the alpha particles went straight through the foil, but some of them were deflected at very large angles--Mrs. K.) Rutherford took a beam of alpha particles and aimed them at a gold sheet of foil to see if atoms in foil would deflect alpha particles.--Adam Choice (Don't forget what he noticed--Mrs. K.) (8) What significant information was learned from Rutherford’s gold foil experiment? In Rutherford's gold foil experiment, Rutherford concluded that an atom is composed of mostly empty space; the atom itself is signifigantly smaller than the space that it takes up. -William McCray (He also found that atoms have very small dense positive centers (the nucleus)--Mrs. K.)

(9) Describe Bohr’s model of the atom. The Bohrs models has an atom consisting of a small, positively-charged nucleus orbited by negatively-charged electrons--Amanda Parker (He thought that electrons orbit the nucleus like planets around the sun--Mrs. K.)

(10) What particle did Chadwick discover? Why was this particle more difficult to identify?

(11) What is our current understanding of the structure of the atom? The protons and the neutrons are located on the inside of the nucleus. The electrons can be found outside of the nucleus in the electron clouds. Protons have a positive charge, Neutrons have a neutral charge, and Electrons have negative charges. Heaven E. (Good answer--Mrs. K)