Physical Science Chapter 4 Test Review Notes
What did the Alchemists do?
\n
They were a group of scientists (alchemists). Sought to turn low value materials, such as lead, into gold.
\n
Who is Robert Boyle? What did he do?
\n
Originally an alchemist but converted to chemistry by another scientist. Solidified concept that matter consisted of indivisible particles of elements. Published a book stating that experimentation should be the basis of science.
\n
Who is Jacob Berzelius? What did he do?
\n
Gave each element a Latin name. Created symbols for elements.
\n
What are monatomic, diatomic and polyatomic molecules?
\n
Monatomic means having one atom per element; there are about 6 of these. Diatomic means having 2 atoms per element, there are about 7 of these, including oxygen and hydrogen. Lastly, polyatomic just means having an element made up of molecules with more than 2 atoms.
\n
What is periodicity?
\n
Originally the false belief held by Dobereiner and later other scientists was that regular trends were found when arranging elements in recurring atomic masses. Now the true definition is trends found when elements are placed in increasing atomic number.
\n
Who is Dobereiner? What did he do?
\n
Discovered a system of organizing elements called triads – 3 elements in a group sharing similar properties. He then prompted scientists to look for regular patterns among elements, sparking the periodic table.
\n
Who is De Chancourtois? What did he do?
\n
He was the first scientist to arrange chemical elements in atomic weight with a cylinder. Discovered that every eighth element shared similar properties with the element above and below it.
\n
Who is Newlands? What did he do?
\n
He discovered that after arranging the elements again in order of atomic mass, that there were pairs with similar properties that differed by a multiple of 8. This pushed him to create the law of octaves which states that when elements are arranged by atomic mass, the properties of every eighth element are similar. However this is false because after Ca, the atomic masses are too great to fit within octaves.
\n
What are the two versions of the periodic law? Which one is true?
\n
Newlands stated that properties of elements vary with their atomic masses in a regular repeating way. This was later revised by chemists after hearing Mosely’s discovery about atomic numbers. It now states that the chemical properties of elements are periodic functions of their atomic numbers.
\n \n \n \n
Who is Mendeleev? What did he do?
\n
Credited as the “father of the periodic table”, he layed out all the elements by increasing atomic mass onto a table. This showed the properties seen across the rows. Then he switched the columns and rows so that now it is like our modern table which showcases elements with similar characteristics in columns.
\n
Who is Mosely? What did he do?
\n
He used x-ray spectroscopy to view atomic numbers. As a result scientists changed atomic mass ordering to atomic number ordering.
\n
How are elements added to the periodic table?
\n
We use nuclear reactions to “discover” (create) elements. This is done by using neutron and alpha particles to upset Uranium and cause beta decay. Many were created at Lawrence Berkeley Laboratory in CA.
\n
What is a family? What is a period? What do they do?
\n
A family/group is a column of elements with the same number of valence electrons. Numbered 1-8A and 1-8B. A period/series is a row with elements sharing the same amount of energy levels.
\n
What are the 3 simple groups of classification for elements?
\n
Metals, metalloids, and nonmetals. Metals make up ⅘ of the periodic table. They are found primarily on the left, middle and left side of the periodic table. Metalloids are 7 elements forming a staircase found on the right side of the table. There are 18 nonmetals on the right side of the table past the staircase of metalloids including hydrogen.
\n
What is the list of families? What are their properties?
\n
Knowt.
\n
What are periodic trends? What are regular trends? Where do they occur?
\n
Trends are the crutches of the periodic table. They are based on the distance between the nucleus and electrons aka bond strength, and the arrangement of valence electrons. Regular trends is the atomic radius decreasing from left to right, EN (bonded atom’s strength of holding on to an electron) increasing from left to right, metallic character, conductivity, and atomic size decrease going down a period, but increase going down a family.
\n
What is bonding? What are the principles?
\n
A bond is an electrostatic attraction that holds atoms together, which also stores energy which can be useful for work, increasing the stability of that bonded atom. Usually, these chemical bonds only involve valence electrons.
\n