Lesson 03.01: History of the Periodic Table Explain how scientific observations led to the development of‚ and changes to‚ the periodic table. Russian chemist Dmitri Mendeleev set out to organize the 63 known elements according to their properties. Mendeleev wrote the name‚ mass‚ and chemical properties of each element on a separate card and arranged the cards by various properties‚ looking for trends and patterns. When he arranged the elements by increasing atomic mass‚ Mendeleev noticed that similar
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Synopsis – Grade 9 Science Term II Chapter 1: Atoms and Molecules Law of conservation of mass: Mass can neither be created nor can it be destroyed in a chemical reaction. Law of constant proportion: A chemical substance always contains the same elements in a fixed proportion by mass‚ irrespective of the source of compound. Atom: The smallest particle which is the building block of matter. The symbol of the element is made from one or two letters of the English
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Unit 1 Key Questions Lesson 1 1. One argument against continuing research on the atom is that the cost continues to increase at an alarming rate‚ and the benefits seem to be declining. Whereas quantum chemistry experiments as early as 80 years ago were very cheap and yielded considerable practical results‚ now very few if any practical results are emerging‚ but the costs of experiments continues to increase. On the other hand
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6 Define the term “atom” and describe its component parts. Ch 3.2 “What’s an Atom?”‚ “What are Its Parts?” http://www.youtube.com/watch?v=lP57gEWcisY&list=PL3FE5B87E56E7A849&index=2 7 Explain how protons‚ neutrons and electrons are arranged within atoms. Ch 3.2 “How do Atoms Differ from Each Other?” “How are the Parts of an Atom Arranged?” http://www.youtube.com/watch?v=lP57gEWcisY&list=PL3FE5B87E56E7A849&index=2 8 Explain how the distribution of electrons in an atom or ion determines the
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quantum mechanics‚ Folger‚ a senior editor at Discover‚ notes‚ an electron‚ proton‚ or other subatomic particle is "in more than one place at a time‚" because individual particles behave like waves‚ these different places are different states that an atom can exist in simultaneously. Ten years ago‚ Folger writes‚ David Deutsch‚ a physicist at Oxford University‚ argued that it may be possible to build an extremely powerful computer based on this peculiar reality. In 1994‚ Peter Shor‚ a mathematician
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3 Questions I have: ● According to Asimov‚ when do people solve problems or make discoveries‚ and why? ● How does Asimov include the scientific information of Archimedes’ and Kekule’s discoveries necessary to help understand them better? ● What was Asimov’s idea behind “Eureka! Eureka!” and how did it fit into the purpose of the story? In the story The Eureka Phenomenon by Isaac Asimov‚ Asimov includes the scientific information of Archimedes’ and Kekule’s discoveries to help the audience und
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organs working together. Organ- made up of‚ similar cells that performs a specific function tissue Cell-fundamental unit of life Organell- membrane enclosed structure that performs a specific function Molecule- cluster of small chemical units atoms held together by molecular bond Deoxyribonucleic acid CH. 2 Matter- anything that occupies space and has mass Element- a substance that cant be broken down to other substances by ordinary chemical means. 92 elements Compound-two or more
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HYDROGEN BONDING: Hydrogen bonding is a bonding type consisting of dipole and dispersion forces. A hydrogen bond is the attractive force between a hydrogen atom attached to a molecule and an atom of a different molecule. According to the Pauling scale of electro-negativities of the elements‚ it can be viewed that the three most electronegative elements in the periodical table are nitrogen‚ oxygen and fluorine. These are also called heteroatoms. The heteroatoms have a partial negative charge while
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Don’t ever simply copy down an answer without knowing how to get there. BUT finally do check all your answers carefully here. You can also read the examiner’s report for each question. 1. (i) atoms of the same element with different numbers of neutrons/different masses (1) 1 (ii) 79Br 35 protons‚ 44 neutrons‚ 35 electrons (1) 81Br 35 protons‚ 46 neutrons‚ 35 electrons (1) 2 (iii) (1s2)2s22p63s23p63d104s24p5 (1) 1
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2: Stable vs. Unstable atoms‚ electron shells Stable Atoms: have 2 electrons max in the 1st shell & all other shells must have a max of 8 - Even # of electrons = unreactive (e.g. Helium: 2 protons‚ 2 neutrons]- Nucleus; 2 electrons]- Shell Unstable Atoms: is any atom that has a shell with an odd # of electrons therefore the shell is not filled to the max - Odd # of electrons = reactive (e.g. Hydrogen: 1 protons]- nucleus‚ 1 electron]- shell Isotopes: Are atoms of the same element but
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