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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....) An atom is the smallest part of matter that consist of subatomic particles. These sub-atomic particles consist of Protons, Neutrons and Electrons. The protons and neutrons are found in the nucleus of the atom. they make up the nucleus of the atom known as nucleons. They are the nucleon number or relative atomic mass found in the period ic table.The Protons, on the other hand, are the proton(atomic) number found in the periodic table. Electrons are found in electron shells which move around in definite energy levels. They orbit around the nucleus of the atom. the outer-most shell are called the Valance shell, the electrons on it are the valance electrons, the valancy of an atom is the number of electrons on the valance shells. The Protons and Neutrons each have a relative mass of 1. An electron have a relative mass of 1/1840, which can be considered negligible. the first shell can hold up to 2 electrons, the second and following subsequent shells can hold up to a maximum number of 8 electrons. In the fourth shell, it can hold up to 18 electrons. The protons have a relative charge of +1, Neutrons 0, and Electrons -1. Electrons and Protons have the same number in a neutral atom, so they are electrically neutral. 2. Draw the atomic structure of a sodium atom and a sodium ion....explain why you draw it this way.   An electrically neutral Sodium atom has one valance electron. hence, it will lose one electron from the outer-most shell to achieve stability.it then forms a positively charged ion. this is because there is one moer proton than electron as it has already lost one. 3. Draw the atomic structure of a sulfur atom and a sulfide ion....explain why you draw it this way   An electrically neutral Sulfur atom have 6 valance electrons, hence it will gain 2 more electrons to achieve stability and form a negatively charged ion. this is because there is two more electron gained in the valance shell compared to protons. 4. Chlorine-35 atom and Chlorine-37 atom are called isotopes...Use these two examples to explain what is 'isotopes'. Chlorine-35 has a relative atomic mass number of 35, that is why it is named as chlorine-35. There is also a atomic(proton) number of 17, this explains why there are 18 neutrons, because the nucleon number is 35 consisting of protons and neutrons (35n&p-17P=18n). Chlorine-37 has a relative atomic mass of 37. there is an atomic(proton) number of 17, which then explains why it has 20 neutrons, because there is a nucleon number of 37 consisting of protons and neutrons (37p&n - 17p = 20n).Hence we can conclude that they have the same number of protons but different number of neutrons. chlorine-35 has 18 neutrons while chlorine-37 has 20 neutrons.by definition, isotopes are different atoms of the same element which have the same number of protons but different number of neutrons. hence, by the chlorine-35 and chlorine-37, we can conclude that isotopes are the different atoms of the same element, chlorine, except that they have different number of neutrons but same number of protons. 5. Sodium is a metal and sulfur is a non-metal....why we classify them this way?? Sodium has a valance electron of 1, hence it will lose electron during a chemical process, becoming a positively charged ion. On the other hand, Sulfur has a valance electron of 6, hence it will gain electrons during a chemical process, becoming a negatively charged ion. Metals like sodium will become positively charged ions by losing electrons on the outer shell while non-metals like Sulfur will become negatively charged ions by gaining electrons on the outer shell. Metals have less than 5 electrons inthe valnce shell while non-metals have more than 4 electrons in the valance shells.Metals, for example, sodium, lie in the periodic table at group I where metals are grouped into groups I, II, III(except boron), with Germanium, Tin, Lead, Antimony, Bismuth and Polonium. Metals lying between the group II and II are transition metals. Non-metals are in groups VI(except Polonium), VII, 0, with Boron, Carbon, Silicon, Nitrogen, Phosphorus and Arsenic. Metals like sodium conduct electricity while non-metals do not conduct electricity except for special cases like water and lemon. |
 Aleen Tan (27) XNPS YHSS Concert Band; Trumpet :) Achievements: 1.EAGLE award 2008 2.Edusave scholarship 2009 3.Edusave scholarship 2010 4.Sports day 2010, 4X100m Silver lowersec girls relay 5.Sports day 2011, 1500m Silver uppersec girls Upcoming Events: 1.17th July 2011 Botanical Gardens performance 2.20th July 2011 International Band showcase Hobby: 1.Play my instrument 2.Side read pieces 3.Listening to songs 4.fishing 5.Doing my own study notes Favourites: 1.White colour 2.Blue colour 3.Adidas Hates: 1.insects I love Chemistry and hope to pass it with flying colours! 3E5 Clasmates 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 28 29 30 31 32 33 34 35 36 37 38 39 40 41 Mr Tan June 2011 July 2011 September 2011 Designer : Chili. x o x o |
