Atomic Structure Assignment(Chemistry Assignment 1)
Friday, July 1, 2011
1. What does an atom looks like? What are the sub-atomic particles inside it.....(talk about electrons, neutrons, protons, electron shells, nucleus....)
-Matter is built up from small individual particles called atoms.Atoms are the basic building blocks of matter.An atom is made up three different types of sub-atomic particles,they are the protons,neutrons and electrons.The proton(represented by the symbol,p) has a relative mass of 1 and a relative charge of +1.The neutron(represented by the symbol,n) has a relative mass of 1 and a relative charge of 0.The electron(represented by the symbol,e) has a relative mass of 1/1840 and a relative charge of -1.The protons and neutrons are found in the nucleus of the atom.These two particles that made up the nucleus are known as nucleons.The protons and neutrons make up the dense core of the atom.The electrons move around the nucleus in definite energy levels or electron shells.The first electron shell can hold up to 2 electrons while the second and third shell can hold up to 8 electrons.The composition of protons,neutrons and electrons in an atom can be determined from its proton number and nucleon number.The proton number is the number of protons in an atom while the nucleon number is the total number of protons and neutrons in an atom(number of protons+number of neutrons=nucleon number).Since an atom is electrically neutral,the number of protons is the same as the number of electrons.The number of neutrons is found by using the nucleon number to subtract away the proton number.
2. Draw the atomic structure of a sodium atom and a sodium ion....explain why you draw it this way.
-A sodium atom has a proton number of 11.Since sodium is in Group (I),it is a metal.Metals have to lose electrons in order to achieve stability(stable noble gas configuration).Therefore,metals lose electrons to form a cation(positive ion).In the case of sodium,it has an electronic configuration of 2.8.1,since it has 1 valence electron in the outermost shell,it gives away this electron to become a cation and achieve a stable noble gas configuration of 2.8.When it loses electrons,it became a sodium ion.This is why i drew it this way.
-A sodium atom has a proton number of 11.Since sodium is in Group (I),it is a metal.Metals have to lose electrons in order to achieve stability(stable noble gas configuration).Therefore,metals lose electrons to form a cation(positive ion).In the case of sodium,it has an electronic configuration of 2.8.1,since it has 1 valence electron in the outermost shell,it gives away this electron to become a cation and achieve a stable noble gas configuration of 2.8.When it loses electrons,it became a sodium ion.This is why i drew it this way.
sodium atom: sodium ion:
3. Draw the atomic structure of a sulfur atom and a sulfide ion....explain why you draw it this way.
-A sulfur atom has a proton number of 16.Since sodium is in Group (VI),it is a non-metal.Non-metals have to gain electrons in order to achieve stability(stable noble gas configuration).Therefore,non-metals gain electrons to form an anion(negative ion).In the case of sulfur,it has an electronic configuration of 2.8.6,since it has 6 valence electron in the outermost shell,it gain two more electrons to become an anion and achieve a stable noble gas configuration of 2.8.8.When it gain electrons,it became a sulfur ion.This is why i drew it this way.
sulfur atom: sulfide ion:
4. Chlorine-35 atom and Chlorine-37 atom are called isotopes...Use these two examples to explain what is 'isotopes'.
-Isotopes are different atoms of the same element which have the same number of protons but different number of neutrons.Isotopes of the same element have a similar chemical properties but different physical properties.The chemical properties of isotopes are similar because chemical reactions involve only the electrons and not the protons and neutrons and they have the same number of valence electrons for bonding.The physical properties differ because the relative masses of the isotopes differ.There are two different types of isotopes,radioactive isotopes and non-radioactive isotopes.The example of isotopes are in Chlorine-35,there are 17 protons and 18 neutrons.In Chlorine-37,there are 17 protons and 20 neutrons.Since there are same number of protons but different number of neutrons,we can conclude that Chlorine-35 and Chlorine-37 are isotopes.And the average mass number of Chlorine-35 and Chlorine-37 is 35.5.
-Isotopes are different atoms of the same element which have the same number of protons but different number of neutrons.Isotopes of the same element have a similar chemical properties but different physical properties.The chemical properties of isotopes are similar because chemical reactions involve only the electrons and not the protons and neutrons and they have the same number of valence electrons for bonding.The physical properties differ because the relative masses of the isotopes differ.There are two different types of isotopes,radioactive isotopes and non-radioactive isotopes.The example of isotopes are in Chlorine-35,there are 17 protons and 18 neutrons.In Chlorine-37,there are 17 protons and 20 neutrons.Since there are same number of protons but different number of neutrons,we can conclude that Chlorine-35 and Chlorine-37 are isotopes.And the average mass number of Chlorine-35 and Chlorine-37 is 35.5.
Chlorine-35 atom:
Chlorine-37 atom:
5. Sodium is a metal and sulfur is a non-metal....why we classify them this way??
-Sodium is a metal because it loses electron to complete the valence shell and become positively charged ions(cations) and it is in group (I) while Sulfur is a non-metal because it gains electrons to complete the valence shell and become negatively charged ions(anions) and it is in group (VI).According to the periodic table,metals are those elements that are in group (I) and (II) and non-metals are those elements that are in group (III),group (IV),group(V),group(VI),group (VII) and group (0).In between group(II) and group (III),there are metals called the transition metals,these metals(elements) are usually coloured.
Acknowledgement:
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