Silvia Juliana Castillo
10
Physical Science
UNIT TEST
1. Make the following problems:
a. 1 atom has 19 protons
What is the atomic number?
The atomic number of this atom is Z:19, because atomic number is the number of protons and z is the number that represents protons.
What is the symbol? The symbol for z:19 is Potassium or K.
b.If the atomic mass is 65 and the atomic number 30?
If the atomic number is 65 and the atomic number 30. First the atomic number is the number of protons, so Z:30 and to find the atomic mass you have to A: P plus N.
So, the neutron would be 35, if uou add 30 plus 36: 65.
c.If an atom has 68 neutrons and the atomic mass is 118. How many electrons does the atom has?
This is similar to the one above. The number of electrons is always the same or has to be the same to the number of protons. So, the number of protons 50 plus 68: 118. So the number of electrons are 50.
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5) Atomic Mass: Is the mass of an atom. However, it only takes into account the nucleus (protons and neutrons), which is due to the insignificant difference of the electron because of its small size.
A= P+N
Atomic number: The atomic number is really unique to every element, and it is the same number of protond an atom has. Z= P
Isotopes: They are the variations of an atom, where they share the same atomic number but the atomic mass is different. So, the difference between an isotope and an original atom is the number of neutrons.
Level: It refers to the seven shells surrounding the nucleus in an atom. They contain the electrons in an atom and they have a maximum of the number of electrons that can be in each level. K, L, M, N, O, P, Q are the names of the levels.
Subleves: It is each division that exists in a level . They are four, S,P,D,Fmaximum number of elcetrons per sublevel also exist.
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3) Using Dalton's, Thomson's, Rutherford's, Bohr's models and the modern model explain the evolution of the atom.
The atom has evolved through time, first it began as the discovery of the particle of which matter was made. Like the greeks said matter was made of air, water, fire and earth. This was the simplest models of all. Then scientists began to discover new characteristics of the atom and its parts. This included neutrons, protons, electrons, levels, sublevels, and orbitals. As scientists learned more about these features, they developed new definitions and concepts as well as atomic models.
John Dalton: He believed that matter was composed of invisible elements, and tried to explain the atomic theory saying that atoms may be distinguised by their mass.
Joseph Thomson: He discovered the electron and used a raytube to prove that the atom was made of small particles. Also, proved that atoms were made out of protons, elecrons and neutrons.
Ernest Rutherford: He discovered alpha and beta rays, identified alpha particles as helium nuclei. Alpha particles are positively charged, discovered the proton. He postulated the nuclear structure of the atom. Small but dense nucleus.
Niels Bohr: He won a novel price and worked with Rutherford. He said that electrons circle the nucleus in orbits called energy leves, and also discovered about radioactivity.