Purpose: The purpose of the lab was to identify seventeen unknown elements, while using limited information that was presented. Secondly, describe the periodic trends and how each of the properties given changes as you go across a period or down a group. Lastly, to explain how Mendeleev used the properties known to predict the existence of undiscovered elements and use this information to explain their specific properties. Independent Variable: The unknown and known elements given to organize. Dependent Variable: The order of elements arranged due to trends and properties. Constants: The periodic trends must be followed for every period and group. The known elements must be placed accordingly. The order of elements that were …show more content…
This means that all of the elements in the same group have a main aspect in common, except for a few exceptions. These elements react with the same specific compounds. This was used to identify the order of the groups from left to right and to determine which elements go under which group. Some research was conducted to identify all the names of the groups ranging from element number one to element number 20. Once all group names were recorded, it was researched which groups react with which compounds that are given on the element cards. For example, it was found that the alkaline earth metals react with O₂ to form XO. From this information, all elements with this reaction could be classified under the second group of elements. Next density was the last deciding factor to determine which elements go into which group. This only needed to be done for hydrogen and fluorine as they were the two elements that did not follow the periodic trend of reacting with similar compounds to form similar reactants. For hydrogen, it is known it is the lightest element from looking at the periodic table, determining it to be the least dense. So, from the two elements left from groups, the element with a density of .0001 g/cm³ was determined to be hydrogen. This was proven to be correct when the density of hydrogen was researched to be sure. This left the final unknown element as fluorine and the density was found to make sure the groups were being formed correctly. So, fluorine was placed in the 7th group on the periodic table being formed and hydrogen in the
each paper remained it's original color, thus concluding that the unknown was neutral. These results also led the students to believe the unknown was CaCl2 since it was listed in the neutral column. After the litmus test was conducted the students added a few drops of Na3PO4 to the unknown. When these two were combined a precipitate was formed. This final test on unknown F verified that it was CaCl2.
Task 1 (P1) The periodic table is laid out into groups and periods. They are also put into different blocks S-Block, D-Block, P-block and F-Block due to their energy levels. They are organised by their energy levels and chemicals properties. As the elements go along the periods in the periodic table the electronegativity increases but as the elements go down the groups the electronegativity decreases.
According to the observations recorded, the metal ion Cesium is present in the “unknown samples”. Unknown sample number five produced a violet color when placed in the flame. Unknown sample number four produced an orange color when placed in the flame. Unknown sample number one produced a violet color when placed in the flame. This evidence supports the claim that the metal ion Cesium is present in the unknown samples according to table two, the Flame Spectra of the Alkali and Alkaline-Earth Elements.
Atoms DBQ Atoms make up every object , substance, and material we know of(O.I). An atom is the smallest particle an element can be divided into. An atom has a complex structure, and the knowledge we have of it has changed many times throughout history. This tiny maze of parts has helped us learn important ideas about the structure and study of microscopic particles(O.I).
There are about 10 Isotopes known to us and half of them are stable. This element is a
Ernest Rutherford 1898 Ernest Rutherford was the founder and investigator of the nucleus. Henry Moseley, Hans Geiger and Albert Beaumont Wood influenced Rutherford. He later discovered that Thomson’s model wasn’t correct and in 1911 Rutherford used his well-known gold foil experiment to prove that the atom holds a very small heavy nucleus. His experiment was designed to use alpha particles released by a radioactive element as probes to the unseen parts of atomic structure.
Dmitri Ivanovich Mendeleev changed the world of science in the late 1800’s. Mendeleev was the youngest of all the children in his family. They lived in a Russian province in Tobolsk, Siberia. His father, Ivan, was the director of a gym and his mother came from a family that made glass and paper. Mendeleev’s father died while he was still young, and Marya had to work.
Copper Cycle Lab Report Ameerah Alajmi Abstract: A specific amount of Copper will undergo several chemical reactions and then recovered as a solid copper. A and percent recovery will be calculated and sources of loss or gain will be determined. The percent recovery for this experiment was 20.46%.
Over our time as students, The Scientific Method was the basis of each and every science class we had taken. This Scientific Method was a set list of steps one must take in order to do any scientific experiment, no matter what the experiment may be or do. Though this is the usual way that scientific discoveries are published, this is not the usual way that science in general is done. In this case, when trying to discover the origins of the elements and find an explanation for how the creation of larger elements is possible, Fred Hoyle and George Gamow are both trying to prove that their respective theories of the universe, Steady-State and the Big Bang, are correct; however, they do not use the linear form of the Scientific Method, but rather
Elements are described by the mass of their atoms – atoms of different elements have different masses. Dalton used the word weight rather than mass. 4. When elements react, their atoms come together in simple, whole-number ratios. This assumption helps in the explanation of the ‘law of definite proportions’. 5.
Our modern one is in order by atomic number. His also only had about 63 elements. Our modern one has 118 elements. Although there are some differences, there are also some similarities. Both
For example oxygen has six electrons in its outer layer because it is located in the sixteenth group or the sixth group if you exclude the transition metals. One could have written out the electron configuration and take the time out of their day or he/she could just find oxygen on the periodic table and see it is in group six. That’s means that it’s has six electrons in the outer
If more number of vacant ‘d’ orbitals are present then there may be difficulty for dehydrogenation process because gases are strongly chemisorbed. VIII group elements contain one e- in their vacant ‘d’ orbital. This is called electronic factor of elements. Second condition is metal atoms should have spaced and ordered arrangement.
INTRODUCTION Gadolinium is a shiny silvery white, malleable, ductile, metallic, rare earth element which is located in group 3, f-block, period 6 and classified in the series of lanthanides in the elements of periodic table and has 27 isotopes whose half-lives are known with mass numbers from 137 to 164. This element is considered a rare earth element because there is such a small amount of it, and it is not found often in its simplest form. It was discovered in 1880 by Jean Charles de Marignac where it was extracted in from the mine located in Ytterby in Sweden, but it was isolated from metal oxide in 1886 by Lecoc de Boisbaudran who named it after the Finnish Chemist Johan Gadolin who discovered the first rare earth element in 1794. Gadolinium
Time has passed since Dalton’s theory have been able to explain some complexion of the atom until 1897 when Joseph John Thomson discovered the electrons which has a huge impact of the existing atomic model of Dalton. From his cathode ray experiment, he learned and discussed about the existence of electrons. Cathode ray experiment explored on cathode ray tubes which are vacuum tubes that consist of one electrode one each side of the tube, altogether consisting of two electrodes, when one of the electrodes or the “cathode” launches electron at the other electrode or “anode”, the voltage is added to the system. While Thomson was performing this experiment, he unexpectedly saw a ray of “light” between the electrodes. At that time, he did not know